1) I paint the faces last. If you make a boo boo, just wipe it clean before it dries and it wipes right off.
2) I did some ornaments with wire and some without. I can't tell a difference with wire so I eliminated that step in most of them. The ribbon seems to hold the sock on just fine as long as you use some sort of sticky tape to hold the sock on. I used Stampin Up's sticky strip tape that comes in a long red roll.
3) I found some of the "fluffier" socks at Walmart but these don't stick as well using the sticky tape. I prefer the Target $ spot socks. They stay on better.
4) That's all I can think of right now :).