[MRBAA]

1) do you play small pairs against a completed bet?

It depends. If I'm last to act, a strong player with a big card in the door has completed and everyone else has folded the I'll fold. On the other hand, if a loose aggressive player completes and gets two callers then I'll call.

2) do you only need one high kicker by 4th street to play on, i.e suppose 5th brings a low, unpaired card?

I play my small pairs in stud about like I do in hold em -- no set, no bet. So if I don't trip up or hit two live pair on fourth, I'm out. Even if I started with an ace kicker, I'll still fold. In most low limit games, you're getting plenty of implied odds to limp your little pair in hopes of hitting. But once you miss on fourth you generally either have many players to beat, meaning reverse implied odds even if you make two pair or you are short handed in which case you probably aren't getting enough odds to continue. Your real value in playing these hands (and the three straights) is that when you hit you'll get paid off -- you're taking advantage of the calling stations who dominate these games by limping alot. You can afford to limp/fold like this because (a) they aren't too aggressive so you often can get in cheap (b) they'll pay you generously when you hit.

3) do you play against a raise on 4th if you get your high kicker?

Again, it depends. When a solid opponent pairs his door and I think it means trips, I'm gone. Otherwise, I'll probably reraise my two pair/with overpair and try to get head up right there. And, of course, this is also a situation where having your cards live is important as you have a redraw even if your opponent hits his hand.