Lizard
As long as you have Pythion built pretty well, you honestly shouldn't really need to worry about any other 60s. Pythion + Rhazin should be enough to bring the boss down, and then you just save your revive for right before the boss dies, revive your team, then finish him off. So, just use those two + three of your 50s.
KR
Lack of reviver is going to make the stage 21 boss tough. Teo should definitely be brought to 60, since he's just so good everywhere, but I'm not sure if you'll be able to 3-star the stage21 boss with those other four 60s + him. I don't think you should focus on this team - I think you'll have a very hard time clearing 21, but perhaps when you finish everything else, just swap your best gear to this team and maybe you can power through.
OG
Similarly to KR, lack of reviver is going to make 21 nigh-impossible. Bringing Klodd to 60 may help you clear up to 20 at least, though, and it's important to be able to farm 20 daily for glyphs.
Orc
Sensing a trend yet? Lack of reviver is going to make 21 very difficult. You *may* be able to brute-force it by bringing Vrask and Garog to 60, but I'm doubtful. I wouldn't bother bringing anyone else to 60, but those two might be worth it just to get to stage20.
SO
As with the others, no reviver is going to hurt. I brought Romero to 60 for a DTH secret room, and depending on your other champs, Armiger and Mordecai to 60 may also be worthwhile.
BL
Again, no reviver is going to hurt, but you have some pretty solid champs here, so maybe you can brute-force your way through. Bring your other two legos to 60, along with Archmage Hellmut. He can stunlock the dangerous minion on the stage21 boss, and between the others you may be able to clear this.