Kat is a total badass. Nice to see her doing her part. That grenade inside the ship had me worried for a bit.
If you want to spare some room for your mission harvests, make use of one of your other bases as a warehouse for excess stuff not in use; from excess weapons/ammo to even Zrbite and Aqua Plastics. They take up a surprising amount of room when not in use (building ships/armor and such, and sometimes, you don't want to sell certain things for one reason or another, especially craft materials. I generally ship units of 50-100 AP/Z at a time until a warehouse eventually runs out of room. I mean, a little soon becomes alot.). Transfer rates are pretty cheap and worth it, especially if you get plenty of excess crap from mission to mission. And it also keeps HQ nice and tidy. Just remember to keep a minimum amount to keep your troops supplied (like 1.5x the amount they need per-mission, and re-supply accordingly)), and instead of buying/building more stuff, just transfer back re-supply from the warehouse for a cheaper price overall, and in less time.
EDIT:
Wouldnt hurt to also warehouse some live alien captures, in case research on some things take a bit longer than expected, and you still want to accumulate a few more live subjects (to sell or for research; should also motivate live capturing for a slight income boost too; mainly selling soldiers or excess higher-ups/terror units, which sell far better than corpses.). My latest XCOM playthrough had me pretty much stunning nearly-every alien I came across.