I don't have Eldoth in my party, but I want to check out Entar's estate and meet Skie. I know she'll call some guards when we meet her, but will we only be asked to leave by them, or are we arrested or forced to fight them or something?

It's been a while since I visited Skie, but if I recall correctly if you don't have Eldoth, she calls the guards and you'll have to fight them - no big deal I suppose. Just once I took Eldoth along and recruited her, just so I could say I'd used all the NPC's.
Sig, have a nice time stealing their loot.