I'm new to this site, but hope you don't mind.
For clapping pullups and so on you need strength, esp explosive strength. Once you can do 20+ pullups, you're more or less going into strength endurance land already. I knew quite a lot of people could do 20, 30+ pullups but not a single muscle up, in fact I was like that too for a while.
IMO the best way to increase your pullup strength is to do harder pullups. There's quite a lot of ways to do it, like changing the leverage (eg 1 hand holding towel), harder variations (archer pullups etc) or adding weight.
At that time I didn't know about all these variations and simply added weight. Weights aren't the best method to use in that they're really time consuming and a bit more dangerous if you fall off, but you can make very small increases in weight and so on.
I can't comment on the muscle up part because I learned the basic muscleup on bars not too long ago. How I got the strength was from weighted pullups.
I wouldn't advise plyo pullups on a doorway pullup bar. Think about it: when you land, the bar absorbs your whole weight and momentum. Even a normal pullup bar shakes a lot if you keep on doing plyos from it, what more a doorway pullup bar? Stay safe.