1. I think it was called 'In which Mercedes is a Yentl' or something. Anyway, she's still friends with Puck after their week of dating and she kinda sets him and Kurt up. If I remember correctly she tells either one of them to convince the other they're worth their time and they do wind up together in the end.
2. Burt Hummel had an accident. It might have been the canon heart attack but I'm not sure. He forgets Kurt completely though and at one point when Kurt is leaving the house to go to school or visit a friend he says something like 'no son of mine leaves the house looking like a...' He regains his memory a few days later. I'm pretty sure it was a gen fic or pre-slash.
3. There's a new girl in the glee club and she wants to date Puck and when everyone says he'll just leave her she says she'll be able to 'tame' him. Kurt however proves that Puck is already 'tamed' calls him over, kisses him and announces their relationship to the club. It was a pretty short fic I think, one shot definitely.
Mods, I hope I did the tags right. Please tell me if I didn't and I'll fix them right away :3