I think Whisper can be run just fine on his own.
If you're planning on making regular TIE Phantoms a thing I would not leave home without at least one or two TIE Advanced to give them something to hide behind when necessary.
Yeah seems to me they'll be most effective as a kind of 'battle line', they're designed to stay in that ideal range 2 band where they can't be engaged (and are free to zoom off and do other things if needed), while something else locks the enemy squadrons down.
