I don't think most people would care about
Hamlet when they met an
Ophelia. I used to work with an
Ophelia (she was of Greek descent) and everyone loved her name. It was terrific.
Gillian - pronounced
Jillian. If it is 80s - and I don't feel like it is, but I see how it could be - it's in a neutral way. It's not like it was ever a huge fad.
Jill is probably not avoidable, unless
Gillian herself rejects it, and you'd constantly be correcting people who say Ghillian. But I like
Jill and am used to correcting people, so whatever. It's a great name.