Oh! Speaking of summons, hopefully this is something triggered by the summon handler rather than a special case somewhere in the AI code... when a creature is summoned, it generally becomes a higher priority target than the player. There are some rather convoluted script work-arounds which can kind of take care of this, but as always a checkbox would be preferred!
I'll see what I can do. Unfortunately, I think this probably falls more under AI than magic, which isn't something I'm well equipped to investigate.
Also, somewhere there must be a piece of data attached to summon X, indicating that it belongs to caster Y. I've managed to extrapolate this data in a script by ref-walking every actor and checking for the associated active effect... but a GetSummoner command would be so much cleaner!
Hopefully this will pop out right about the time I figure out why summons don't cause savegame bloat. Be warned, though, I've seen nothing to indicate that such a 'my summoner' field exists. It's perfectly possible that the only link between an actor and their summon is the active effect itself.