No Please note that ally lists are not reciprocal, in other words it is possible for a race to appear as allies of another race, while not having that race in their own ally list. This simply reflects the fact that to get a race as an ally there must be a good chance of a small contingent of their troops serving in a large army of troops drawn from the main list. In the case of Dark Elves and Skaven, for example, it seemed sensible to me (Jervis) that small contingents of Dark Elves could serve in a Skaven army, but not vice-versa.

No.

Characters can join either unit, but note that with the exception of Champions they will not benefit from the unit's special rules. Thus a character with the Scouts can't infiltrate, and a character with the Dark Riders can't make a free march move at the start of the battle or fire and flee.

Yes

Yes.

Yes

The Witch King always comes with the chariot, but may leave it voluntarily during the battle.

The panic test is taken first, and if passed, then the must charge the enemy test is taken.

Yes.

The Witch Elves lose hatred when they frenzy.

Yes, he can be challenged.

Dark Elf Assassins can hide in the following units: Executioners, Black Guard, Corsairs, Warriors, Spearmen, City Guard, Crossbowmen. It should be noted that Dark Elf Assassins are male, and cannot disguise themselves as scantily clad female witch elves. See e.g. Warhammer Armies: Dark Elves, p. 40 "the Witch Elves steal away the male children who they raise in the temples of Khaine."

No.

No, the Witch Elves strength when attacking is 4.

Yes, but not their magic weapons (see Assassins above).

The only Hag Queens that can be purchased are the special characters listed.

Yes, he must take this as equipment. It costs 5 points. It is considered magical, but does not fill his magic item slot. No other Dark Elf characters may have the cloak.

Yes.

6.