I also bought Shelves on accident (it was on sale!) so don't feel bad. ;-). I'm sure it's a good module, but it overlaps other stuff I have. I don't have the version with the expanded filter options like you do.
I don't know Yarns but if you are using a computer with this or external sequencer I hear it is very good. I use a Beatstep Pro and a Rene myself. It's all personal choice of course - I don't do live performances. :)
Mutable is very nice stuff - I have Clouds and Braids and thinking of Grids - but I also like the more "raw" tools like Maths, and dedicated VCOs and filters. Anyway - good luck with your choices!