So the title says it all.... I am especially unsure if I should get the WL Random or just get a white noise generator with a sample and hold module. If this is the case I would need to get a clock or gate generator of some sort which I know nothing about. Maybe instead I should get a Pico trigger and seq?
Any help, opinions or tips would be very welcomed!

Here is the rack, I have no idea how to post it here:

Don't purchase anything. It feels like you're throwing modules into a rack and hoping that something useful takes shape.

The Mutable Instruments Clouds module is no longer available. However, you can purchase it used or better yet buy a 3rd party micro version. Look for a Michigan Synthworks uBurst or the like.

My advice would be to download VCV Rack. It's free. It also has a virtual version of Clouds. Look for some ambient tutorials on Youtube and start practicing. Once you've learned HOW to make random ambient textures in VCV then start looking at putting together a system.

I have been playing around with VCV rack, that is where the idea of randomly generating patterns with white noise and a quantizer into a VCO pitch and Clouds came from. What did I do wrong and what do you recommend?

What's your budget excluding the case? Clouds is a stereo module. Will you be satisfied with a mono output? Are you using the white noise generator as just as a random voltage source and/or an audio source?

I was thinking of about 900-1300$. I do not mind mono outputs and I think big stereo integration would become a bit expensive, but a stereo mixer as crossed my mind to be honest. And primarily as a random voltage source with a quantizer, although a sequencer with a trigger also might be an option (The pico ones).
Thank you in advance by the way!

ModularGrid Rack
I've been over this a few times... made some revisions... thought about some things. It's more than you want to spend. But your first case is always the most expensive.

Let's not go random. Let's use a sequencer. In fact, let's go with a good sequencer. The 1010 Music Toolbox is $600. Perfect Circuit will discount it to $500 once in a while during sales (Christmas etc.). There are 8 gate outputs and 8 CV outs. You can multiple sequencers running at once. You can have LFOs, random CV, notes (CV and gates)... you can even sample control voltages, record them, and then play them back in a loop (works for audio too). It'll cover a lot of modulation sources, which you'll want for evolving stuff.

Braids. Braids is a workhorse of different sounds. Having a multitude of different sounds will give you a much wider palette than a basic oscillator. Braids also has a built in internal quantizer just in case you really do want to go random... I didn't forget.

A simple multimode filter. Not thrilling... but filters can create a lot of movement in ambient sounds. It will output all three filtered outputs at once (modulating two or more with two VCAs can be tasty).
Z4000 ADSR with nice long stages available. Plus you can modulate the amount each stage.

Intellijel Quad VCA. This is the one to get. It's very versatile and can even sum outputs.
A-138s stereo mixer. Mono-ambient sounds... (yawn)
Pittsburgh Modular Lifeforms Out. If a tree falls in an oscillator and there's no one to hear it... it's also stereo and has a dedicated headphone jack... very convenient when you're tweaking and wiggling away.

There's a lot more you can do with slew limiters, other FX, more ADSRs, dedicated LFOs, etc. But to me this set-up will be fast to learn and give you a lot of possibilities and will grow with you into a larger case. I even left you 6HP of space. :)

As always, take this with a grain of salt. Research everything.

1010 Music Toolbox $599
Michigan Synthworks uBraids II $250
2HP MMF $119
TipTop Z4000 NS $165
Intellijel Quad VCA $189
Doepfer A-138s $90
Pittsburgh Modular Lifeforms Out $99

And if I might, I think I have the perfect solution for that open 6 hp: Feedback's 106 Chorus. An excellent addition to an ambient-focussed system, with mono in and stereo outs, based on the Juno-106 chorus circuit. Paired with the uBraids, that would nail the effect processing situation nicely!

One other thing, also...the Toolbox is a nice idea, but having just one oscillator really undertaxes it. Instead, jamming that space with 2hp modules would allow for three sources (VCOs, or a mix of VCOs and some of their other things like the Vowel or Pluck) and a 2hp Mix to sum that down to the MMF for a nice paraphonic-type voicing. Yes, a bit more spendy, but the capabilities would really jump up at that point. You could also drop the Z4000 and go with a couple of Ladik modules; a C-214 replaces the ADSR capability of the Z4000, then tossing in a C-041 adds two AD/AR envelopes that can also function as LFOs if they receive a constant pulse from the Toolbox.

Wow guys I was not expecting all the trouble you went trough thank you so much for the help! As much as I love the toolbox idea it is a bit out of my budget right now. What do you think of using marbles and get one more oscilator? I could even get a pico drum to get some lo-fi rhythms going on. I am still exploring and getting to know modules while experimenting on vcv rack so new ideas keep coming! I also love the juno chorus since it was my favorite thing about the tal-u-no-lx plug in. I was even thinking of getting the upcoming tc electronic pedal for my guitar based on it!

I was just about to suggest Marbles for you... the thing is amazing. Also: can be had on a great discount at Juno Records in the UK (with cheap shipping if you're in the US). more shot here. I blew your budgeting all to hell, but I wanted to suggest what an instrument of the sort you were discussing could actually be. Here it is...
ModularGrid Rack
Now, you'll notice first off that the case is different. Instead of a Doepfer 84 single row, I went with an Intellijel 4U/104. This opened up a bit more space, plus added the Intellijel tile row for some extra functions, and it's fully-powered with Intellijel's excellent integrated supply/power bus. From left to right up there, you'll see your main clock, noise sources, a slew limiter, sample and hold (in the first tile alone, too!), a 4 x 64-step trigger sequencer for your drums as well as clock modulation/tinkering, a Quadratt which is your CV linear mixer/mult/inverter, then the line in/out which uses the Intellijel case's I/O jacks, already built in.

Bottom row, left to right again: the Permutations is a generative randomness sequencer based on the popular Turing Machine, sort of a 2nd-gen version of that. This provides loads of random and psuedorandom (at varying levels) CV possibilities. Next to this is a Toppobrillo Quantimator, a quantizer with scaling/tuning/chordal control via CVs, plus three outputs which can also be fed via an analog shift register, a sample-and-hold-type device which feeds CVs forward by a step on each clock pulse. These three outs are also your chord outputs, as well.

And with three outputs, you need three VCOs. I opted for the Noise Reap uBermuda here...very cost effective, plus they have a very crazed self-regen control that can drive the VCO waveforms into some really nasty shapes for lots of distortive harmonic fun. Audio mixer is next to these to sum your VCOs down.

The Delptronics LDB2 setup is next. This is a pair of modules (voices and CV expander) that offers analog sounds in the typical Roland 606/808-type family, with CV control over numerous parameters. Next is a pair of linear VCAs, to be used with CV/mod signals to control their levels. And for modulation, that's now fairly comprehensive: a Takaab triple LFO, Takaab CVable A/R envelope, and dual Doepfer ADSRs. Note the location, also...the Quadratt is directly above so that you can easily route your mod sources into it to combine them.

More Noise Reap...state-variable VCF with three frequency CVs, plus CVable resonance. Another audio mixer allows you to sum the outputs from this along with the mix out from the LDB2, if you choose. Right next to this is a switchable linear/exponential VCA with built-in AR envelope for your outgoing audio level control prior to the effects: 106 Chorus (again) which can stereoize your mono audio to feed direct to the uClouds SE for more processing, with the audio outputs directly above for convenience.

Yes, I know it's about $1500 more. However, this is the sort of thing you're actually pointing towards with the ideas you'd mentioned, so I thought you might like to see a reference of what this might entail. Oh, and as for the passive mults...there are none. In this tight a space, it's best to use inline mult widgets so you can maximize your active functions. And while there's buffering on the Quadratt output(s), there's no buffered mult because you won't be connecting CVs across so many modules that would cause voltage sag.