i think danny can tango. he just seems like he could. what do you think?

I think he could. With all that grace and the emphatic body language he uses?

so does danny know the name of the bands they're playing, or the names of the songs even?

I think he would. If he's spent any amount of time at all hanging out in Sullivan's (and I get the impression he has), he's probably gotten familiar with a lot of the stuff they play. So the two bits you quoted would be totally believable with specific band/song references thrown in.