1) Hard to say, exactly. Communication is key - I wasn't absolutely sure I could manage Fluttershy until we ended up having a conversation that had no relation to either her canon or Milliways.

2) There are so many options, but at the moment all I can come up with is "any canonmate". Except Rydia, from Kain's canon. That would be... complicated until both are past a particular point in canon.