My banshee has done well sometimes in lower crypt fights but I can't really judge her ability to take down a line, has been really random. Doppel I still send solo vs surviving spectrals below O8 (at that promotion doppel green will miss). Just do the fight manually and take off auto since you don't want to transform.
I still find snap more useful though since he will stand in front when hiring a bard in crypt. Once he even executed a ninja but that's super rare these days since the execute range is really small. Snap and zombie at O8 is mostly for my crypt but zombie I may use in war too on some 3x crab weeks.