I've only seen the options in the character file drop down for Humanoid and Legacy. Are you saying you can set the fbx rigs to Generic then use Humanoid or Legacy in UFE character settings?
Unity Humanoid quality is okay if you really need to share animations from character to character within Unity but in order for it to work perfect they still need to have the same skeleton hierarchy and rotation axis. The down side is your animations are not one to one. Humanoid has degrees of freedom setting for the bones that will limit the bone rotations regardless of what your animation does. There are setting for it but I've never gotten them to do what I want.
For example if you have a sub object in your FBX of a melee weapon that's not part of your character skeleton hierarchy and in your animation it lines up with your hand. When you put it in Unity with Humanoid as the rig the hand and melee weapon wont line up and they'll be offset.
UFE supports legacy in the character file and this is what I've switched to using. My animations are 1 to 1 and any sub object I have as part of my character lines up where it should.