So we this is the order you'll prolly do it in
16 Doors (50 cap)
Bugbear (50 cap)
Mithra (50 Cap)
Snoll (60 cap)<---------- probably do next time /hurray for AF
The Bugbear/Moblins are 60 cap

Since we plan on doing the 50 cap Spiral.. the only other 50 cap part is the 3 Mithras.
If it is getting late, rather than have to run all the way up the hill and fight the mithra, we could go on to do the uncapped battle in Delkfutts Perhaps? There is a bit of running around to do before that battle so that will take time too.
Whichever way we decide to do it, just wanted to clear up any confusion on caps.
Moblins/Bugbear =60 cap
Spiral (Tower J8) = 50 cap
Delkfutts Tower NM (Disaster Idol) = No Cap
Fenrir Gate (Tower H-10) = 60 cap
Mithras = 50 cap
Snoll Tzar = 60 cap
Also if you have done the prerequisites for the Quest "Return to the Depths" you can use an Ahriman tears to get to Mine Shaft 2716 for the Moblin Bugbear BC. Or you will need a snow lily.