The CA hinges in my UCD kit were one large piece that you have to cut out into individual hinges. Mine was inside the same package as the instruction manual - you may not have recognized it as the hinges. I would not recommed using them though. I have had two break on an elevator and two on an aileron. I don't hate all CA hinges, just the GP brand. Sig Easy CA hinges are nice. For an alternative to CA hinges, I like both the Robart "Point" type hinges and the Dubro door-hinge style. I used both of these alternatives to replace my broken GP CA hinges.

As for the pants, yes, the wheel collars go inside the pant. This is a real trick, as it is difficult to thread a collar, wheel, another collar, and the pant all on the axle at once without dropping the collars a few times. That's right - each wheel gets two collars to hold it in place (it sounds like you may be using one, which would cause the rubbing problem). The two collars inside the pant should be located to keep the wheel from rubbing the pant. It sounds like you are using the wood piece with the hole correctly, it should be glued inside the pant so that the axle end just sits in the hole. Since I fly off grass, I skipped the pants altogether. The UCD is so damned ugly anyway that it doesn't matter!

Hope this helps,
Kurt