1) Not that I'm aware of, no. It's a drawback to a spell that gives you unmatched stealth. The master of dimension spell does remove the lag from where "name," but that in and of itself makes it worthwhile. One or two round lag from each command when trying to see if anyone is in the area can hamstring you quite a bit. If you're good at scripts, you can put together something where you do who pk and it'll automatically do a where on everyone on the list. You can likely do something similar with a set of targeted aliases, where you manually put in a list of names to check for and then one command will check where for them all. I'm not that great at either, so have never done it, but it's possible and with the master edge a huge help.

2) So far as I know, any area spell will take you out of duo. Damage or revealing. You'll also get the lag from coming out of duo dimension, so careful.

Something to keep in mind, and that still kills me every now and then when I get forgetful about it, is that considering a mob will ALSO take you out of duo. Do that in front of a big aggro mob, and...