Ophelia- I think even if people
are aware of the Shakespeare connection, they won't think the name is lame because of the character. If anything, they are more likely to say, "Oh, a Shakespearean name! That's cool." Also,
Ophelia is very pretty and not overused, so keep it on your list.
Gillian- I don't think it's too 80's; when I was a kid in the 80's, I never met anyone with this name. I think the 'G' spelling gives it a romantic, medieval feel without going overboard, and I've grown to love it. If I had a daughter tomorrow, this is what I would name her.
I don't think any nickname is inevitable if the kid corrects the people who use it. Not a big deal.