We are losing two of our players until midsummer. That leaves us with a rogue and a hedge witch. The hedge witch player hates dealing with summoning and her only damage so far is from vomit swarm. Any idea of what kind of adventure I can throw at these guys that will be a decent challenge for a rogue who will almost never be able to flank and a witch who likes to heal? I've got plenty of story ideas but I don't know how to give them some good fights. Should I just run a character, a fighter maybe? I've suggested they make new characters for the interlude, but they like the ones they have.
Yep NPC guest stars is the best way to round that out. I'd suggest seeing if the players want to run these NPC allies for combats.
Have them temporarily recruited by a gang- thieves or mercenaries, or even the town guard.