After checking probably a hundred systems, I have found three possible candidates.
1) Tulikov - Binary
Distance: 18 (system view, for reference, originally it was 6)
Has a large asteroid belts in both of the planetary systems and plenty of moons and habitable planets. However, everything tends towards being a little low gravity with most under 0.6 gravity. This isn't a big problem, but it means I must either make my Wrix low-g wusses (bleh) or generate them on a higher g world, before moving them over. Feels a bit like cheating.
2) Lick - Terniary
Distance: 15
Has barely sufficient habitable planets and relatively few moons and other orbital bodies. No asteroid belts. The third star is not a problem as it is very dim and very distant at 19600 distance. Gravity is also low on all bodies. Interestingly enough, the 3rd star actually contains an additional two habitable planets. I'm just worried about a mineral crunch on this one.
3) Arecibo - Binary
Distance: 4
Large asteroid belt in the primary system and a small one around the secondary. Great variation in gravity here, with both a high-g and a low-g planet in each planetary system. This one seems extremely promising, but it has a few flaws. The secondary is a bit empty with only a single moon and 3 planets, the distance is perhaps a little too close and if I do pick this one, I will have to make the Wrix have extreme gravity tolerances (0.35 - 3) which could be a little strange.
I must say, I like the last one despite it's flaws. What do you guys think?
Edit: Feel free to post in this thread. I'm going to start a new one when I get started with the actual story.