If I may please; as I am new to creating "my own" character models; I have a couple questions about the process before I begin so that I get things right sooner instead of later

1: When modeling clothes and gadgets from scratch; is there a particularly accepted method for attaching them to a character's rig so that the character's underlyning skin doesn't pierce through during animation or kinematic changes? ( if it helps to visualize; imagine a small team where: Artist_A does animation, Artist_B creates the character models in MH, and Artist_C is responcible for combining everything together so that motion capture specialits can bring them to life )
2: if memory serves; iPi uses a specific rig for their animiation software. Does anybody have experience in bringing that TRS animation data and applying to a MakeHuman rig? ( this would be my first time and I'm willing to wager that the two Rigs are very different in design )
3: Facial animation; I truely haven't ever done this before in my career and I would love to get started if someone could point me to a tutorial or forum topic, I would much appreciate it