Random questions, but in my inventory have a ton of items, including many philters, pies, traps, etc., some of which are tradeable, and some of which aren't (from like the advent and stuff). My question is, if I'm using say, a trap while in explore, how does the game pick which one to use from my inventory? I'd prefer it use the non-tradable ones first, does it matter on the order they are sorted in my inventory?

whichever of the stacks is first in the inventory gets used first

Ah that's great to know, thank you very much! ^^