Nice. Besides big return pump advice you've gotten, possible issue would be how you'll handle the overflow prefilter. I use window screen now and its much too big to breed shrimp in the main tank, and puffers are also small. So best to use sponge or such on those prefilters, which you'll need to clean regularly (baby shrimp are about the size of the particles you want in the sump). May be best to split the line going to the 5.5gs (like theyre in parallel) from the main drain of the 90g, limit flow with a ball valve to those tanks, then join their drains to the main drain line.
Since you're thinking of up to 4 tanks on that sump, suggest you add a fifth and plumb it in a way so it can be disconnected from the system and used as an instant
QT. Maybe even add a sponge filter so its ready to go when needed.
With all that piping and several tanks, you'll probably need many gallons of saftey room in the sump should you lose power to the return pump(s). With that in mind, a ~100g trashcan in the basement as a sump might serve you better than the time to
DIY a 100g or more sump thats only 2/3 or less filled.
Best to plan your 10g planted tank as lower light too, since it'd be a PITA to dose macros with that volume. Easy enough to experiment with more lighting later if wanted.
Just thoughts.
HTH