I've been catching up on this thread today, and I think anyone who can nurture wild animals in their home is very clever and patient. The only wildlife I have kept indoors with any success are spiders and, when we had a cat, fleas......
But on the subject of ticks, I found the easiest way to remove them from my dog was indeed covering with Vaseline (just the tick, not the dog) so would think this the least stressful for the hedgies too.
I found a sick woodpigeon once and took it to my neighbour (as he kept chickens) for him to take care of. He did, but not in the way I had hoped.....
Best wishes with your little charges, Schmoo!