@Calavente
In most civilizations only melee units can upgrade to UNITCLASS_IMMORTAL, but there are exceptions among the unique units of certain civs. The Illian/Doviello Priests of Winter, the Elohim Monks, the Amurite Wizards, and the Calabim Blood Guards can also upgrade to this unitclass.
Thanks to Blood Guards, it is not much harder to get Vampire Lords in this modmod than in base FfH2. This UU starts with the Vampire promotion and has the same tech prereq as the old Vampires, although they cost slightly more and, like the Royal Guards they replace, they are mounted national units that require the Aristocracy civic. (This is the favorite civic of the Calabim-only leaders and is thematically appropriate, but was mechanically disadvantageous until I added this UU.) Blood Guards lack the Spirit II promotion and the strong defensive strength of the unit they replace, but they still start with Guardsman and Law I (which very useful when dealing with the Moroi's and Brujah's Burning Blood). Using them you can get Vampire Lords with promotions like Mobility II and Flanking as well as Law I, but since they no longer have Channeling II this does not give them access to Summon Einherjar or Unyielding Order (unless they use the Death III spell to turn into Liches)
@Cutlass
Units graphics reverting to those of vanilla civ is a known issue not only with my mod but with FfH2 in general. It happens when you have the Frozen Animations graphics option on, as those who made the custom art for FfH2 dd not bother to create frozen animations.
I always turn videos off, so I have not encountered any problems with wonder, religion, or ritual videos. Someone commented a while back that there was an issue related to the lack of a video for the white hand founding, so I just copied another religion's videos for the new religions. I don't know why they would cause a graphics card problem. I would just suggest turning the movies off. I do not think that they add much.
@Conqistador
Return of Winter works fine for me. I believe that right after my last release I noticed that the map still contained ImprovementType=IMPROVEMENT_PENGUINS when it should have been changed to BonusType=BONUS_PENGUINS (which I have since corrected but not releases), but the error that generated should not stop it from loading.
@TheLazyHase
Disrupt was not removed, but rather moved to be a spell used by the Agents of Esus.
I'm not quite sure what I'll do about Loki. I already gave him Mind II, but I still tend to think that he is not worth building when I play as the Balseraphs and too annoying when a Balseraph neighbor sends him to my cities.
I am tempted to give Loki Chaos III, so that he can cast Wonder. That would of course necessitate making him a later game hero. Drama seems most thematically appropriate technology, but it might be too early for a spell as powerful as Wonder. I just noticed that it is possible to give multiple tech prereqs. Is Drama + Sorcery enough, or would Drama + Arcane Lore be better?