I can't answer all of your questions, but the silly tango your toons do is generally caused by the way IWT works.

Basically, if you tell your slaves to IWT with a target, and that target moves, even in the slightest, the game engine has told those characters to keep moving in X direction until they hit that mob, so if your tank accidentally turns and slightly moves an enemy, after you have told your slaves to attack it, they will probably run off.

It's a fine art, but I find the old "follow active character" function in is boxer helps as it makes them come to you (however that's with 5 melée)