well technically Yen'fay is still dead and this is an alternate timeline Yen'fey… Aversa they were too busy with the giant flying god of destruction and likely didn't really bother checking to see if she had a pulse. Emm had the excuse of she was probably saved by some inspired Pelgians who tried to pretend they didn't know who she was to protect her from reentering the war. It's implied that Walhart may be a risen but his will was strong enough to retain his humanity even after being revived. The only one with zero excuse is Gangrel since considering all he did I'm quite sure Chrom would make damn well sure he wasn't getting back up once they cut him down.

for me, a somewhat good idea for them was to pull a yen'fey spot pass. make the characters alternate versions with different personalities Emm's memory loss/broken speech being untouched
like Gangrel's outworld self showing actual remorse/reform upon entering the main world for example.