I am having mixed feelings here. On one hand I admire your brave and interesting plan to simulate two Matriarchs and SQ-1s by using a Eurorack modular synth, on the other hand, I agree with Lugia, it's kind of expensive...
Let's put it like this, if for some good reason (for you that is) you still want to follow up on your idea and not going the road, for example Lugia advised you to take, then let's assume money isn't the biggest issue. So from that point, I then continue:
The most obvious thing that I noticed from your here above displayed rack is that you are having two MIDI interfaces A-190-5's here. I really think, and I usually like to have from good modules more than one if financially possible so I am not saying this easily but here I do, that you can get rid of one of those MIDI interfaces of A-190-5. One should be sufficient, use that in combination with for example a Kenton - MIDI Thru 12 then you have enough MIDI connectivity and possibilities from that point of view. Kenton has a few different MIDI Thru models, check the one that suits you most, the MIDI Thru 12 is just an example here.
Though I am usually certainly pro Doepfer, I have quite a few Doepfer modules, however there is just one Doepfer module that I seriously don't like and that's.... yep... that's the A-190-5 or rather the entire A-190-x series. That doesn't mean you wouldn't like it but check this module out if this is really what you want. I had this A-190-5 for a short while in use but it just didn't work out for me. For my understandings, it was not logically to use. So that's the only module so far that I had exchanged for another one, I took the Vermona - qMI2 instead. This module is straight forward in its usage, very logically, just easy to use. The A-190-5 is exactly the opposite of it... but up to you, just check if it's really what you want.
Is this for you a kind of side project? Meaning, do you have already one or more racks full with modules and this is an additional project? Or is this going to be your first Eurorack? In case you have already one or more racks, then go ahead as planned, perhaps fine tune it here and there and perhaps some other members have some more suggestions. I don't have myself the Matriarch neither I have the SQ1, so I can't really, at least from an experience point of view, take these two devices, to cross-check them for you if you have covered everything.
If this is however your first Eurorack, and again, if you don't mind to spend this kind of money, then I would advice you to go for the Doepfer A-100 PMS12 PSU3 rack, that one has one more row that you are going to need in the future for possible extensions, at least you don't need to straight away buy another rack again. The second reason to go for this rack instead of the PMS9 is that you have here 4 PSU3s, so you have on average per HP a bit more power supply (i.e. mA) available, so you don't need to worry too much about the power consumption of modules. The Doepfer A-100 PMS9 and Doepfer A-100 LMS9 are good deals if it comes to bucks per HP however because of that you have to be a bit careful regarding the power consumption with these two latter mentioned racks because they only have two PSU3 power supplies (PSU = Power Supply Unit). The PMS12 has sufficient power so you don't need to worry about that.
Either way, if this is your first rack or your x-th rack :-) My advice is to start not to buy everything in one go but start for example with simulating first one Matriarch. When that works, you are happy with it, fine tuned it, gained experience, etcetera, then add the SQ1 part to it. Then again, check that and if these Doepfer versions of Matriarch and SQ1 works out well only then buy the modules for the 2nd Matriarch and SQ1. In that way you spread the risk and taking it a bit easier on your finance, should something disappoint you somewhere down the road.
Again, please reread Lugia's post, he really got a good point there. Yes this is kind of interesting but is it worth it?
However if you set this for yourself as a kind of milestone you want to do just pure for the fun of it, why not? :-) Eurorack is all about experimenting and having fun :-) I wish you good luck in that case, please keep us updated about your progress and kind regards, Garfield.