I mean, there are ways to count as wearing armor even though you are technically not wearing armor—warforged feats come to mind—but I'm not sure how that would accomplish what you want.
This is a function of Spellcraft.
MIC has rules for slotted magic items on nonhumanoid body types (page 219). It also stipulates that manipulation activations require a free hand (page 220). Command and mental activations should be unimpeded.
No. You have to succeed on a swim check in order to move the extra 10 feet. Since you don't roll swim checks at all, you cannot succeed on one, so you cannot use the skill trick. (You can make swim checks to avoid obstacles, but the trick only cares about swim checks made to move.)