Artak should be a priority since he does well in all dungeon content that drops gear as well as minotaur.
Corvis would pair decent with Artak, especially for waves. Apothecary and Ronda for your Fire Knight teams, especially with Farakin the Fat. Don't need to put Skill Times into Ronda for her to be useful there but definitely max Apothecary since he works well on most dungeon teams also.
You've got Maneater and Painkeeper, so as long as you can meet the stat requirements you can pair them for your Clan Boss team once both are 60. Here's a generic template you can follow for that:
https://deadwoodjedi.com/speed-tunes/budget-maneater-unkillable/
Wukong and Rathalos are great boss nukers and Wukong is also really effective at clearing Rounds 1 & 2.
Scyl is always good in almost all content.
Stage 16 is the best to farm if you can't do Stage 20 and that goes for Fire Knight, Ice Golem & Dragon. Especially since Stage 16 is Void so Affinity isn't important. Here's the teams I'd run on Stage 16 for each of those dungeons (and then 20 once you've got your characters booked out):
Dragon: Artak, Scyl, Wukong, Ghostborn and Rathalos
Ice Goelm: Artak, Corvis, Scyl, Rathalos and Visix or Alsgor. Key here is that Rathalos is gonna upset the Ice Golem and he might do two attacks in a row so with Visix Ally Protection or Alsgor Block Damage you won't die
Fire Knight: Visix, Ronda, Apothecary, Farahkin and Artak. I didn't see Coldheart but once you get her swap her for Visix. Make sure Farahkin doesn't use his A3 on Round 3 so he can use it on his first turn on Fire Knight to get rid of the shield. Visix should mainly do her A1 to keep reducing his Turn Meter and her A2 for Decrease Speed, turn off or don't use her A3 on the Fire Knight himself.
Minotaur: Use the Dragon Team
Spider: Artak, Wukong, Rathalos, Visix and Apothecary. See if you can have Wukong and Rathalos focus the main spider while Artak burns+activates burns on the spiderlings. Use Visix for Turn Meter and Decrease Speed, Apothecary to go more often + Heal