I assume you already know about ctrl+shift+k to auto-kill enemies and ctrl+shift+r to resurrect people in case you aren't testing balancing, but rather only logical outcomes.
I don't have a good answer about testing balancing, except that when I get to that point, I will probably create a debug book where I can, via dialog, hand craft a party and spawn in heroes of the specific level and basic build similar to companion recruitment in Origins.
You might also get some use from the
editor console for helping out with some character manipulation.