Reaeguard for dwarves, drop one of Hurndig/Trunda/Geo.  Melga, Brogni, Rearguard can probably carry 2 commons lol.  

Dark Elves, again looks like you are too attack heavy.  My strategy for all crypts was support/defense.  Slow and steady... Visix is solid here.

so...you 3 starred boss but not 18-19. Unbelivable.

Weird right?  I think the big difference is that with the boss, it is only one enemy hitting my squishiest champ. So I have the ability to revive and then shield quicker. 

ohh. I see. 1 boss vs 5 champs at last wave. fw 21 vs 19-18. How did u 3 star 20 then?

for 20 it was either luck, or just the right mix of enemies

swapping Rearguard for Hurndig did the trick on floor 18 (ran out of keys so haven't tried 19 again yet)

I think my dark elf roster is still lacking right now... I did pull a Kaiden that I haven't leveled yet

Dark Elves was the 2nd to last one I finished, so I said F it and 6*'d Kaiden and Visix.  I was too close to Lydia.  I don't see a use for Kaiden outside of FW, so don't recommend leveling past 50 unless you are near FW completion and desperate like I was :)