Not exactly sure what you want people to say here. You see these cards over and over because they are the most efficient choices for DT. The reason you don't run things like
Jackie Cr or
Zatman is because there are massive penalties per round for running these and they aren't worth it.
Zatman is a -2 penalty, so if you play 20 rounds or more that's -40 points (or more) during the duration of the tourney. The difference between
Jose Star and
Zatman doesn't justify a -40 point deduction.
As far as why you see Junks and
Uppers so much, the bonuses are very effective. Thinks like
Freaks,
Pussycats, Frozen ect are not as good for fast play, since their bonuses just slow down or encourage bluffing/no pilling. Then your opponent spends time thinking about what you are going to do.
And lastly for how to pill the Junks characters or win with them, this question almost makes me think this whole post is a troll because, really, how can you answer this question? You spend your pills where your think it's worth it and don't when it's not. That's what the whole game is about, so there's really not a good answer imo.
Flanagan is lower dmg so it's a good opener 0-3 pills or used as a wall vs a dangerous card to negate it's bonus. The rest have reasonable dmg, power, and great abilities, so it's hard to say a hard and fast rule how to play them.
I hope this helped, but all the questions seemed so obvious and general that I'm not really sure.