Yes it absolutely could, but the character must use a single 'skeleton', meaning the character can only be made pieces of similar bodies. For example I used the Humanoid1C skeleton, meaning I can use parts and animation from chunky male models i.e. chaos, norsca and a few kislev units like kossars and boris.
Realistically the best options would be a human or elf, as those skeletons have plenty of models ready split into head/body/legs, and animations ready made.

Back when I first started making this months ago, no, the two lords would rapidly flicker between the two models you gave them. But I have a hunch CA might have fixed that with the IE update so may be someone will try it.

Unfortunately it seems not, while I have never tried it myself someone on the modding discord did and couldn't get it to work.

If it's some kind of stick held in a hand then probably, but if it is built into the character model it gets far harder to add.

Yes but each lore will show up in it's own tab. Basically there are two ways to make multi lore capable lords, the Mannfred way with two switchable spell lists, of the Teclis way with many spells from different lores on one list, with 6 max. So in the end I decided to go with the first option as it gives the player more options (e.g. Mannfreds sword can be used with a staff to give darkness+whatever magic), but I can change it if players would rather have the other way