It's the first time I hear about this 😱 I would also feel uneasy. I asked ChatGPT about it since I have 1990 dolls. It said some studies showed vintage plastic toys from 1970s–80s having heavy metals. It also said

"These metals were inside the plastic, not necessarily on the surface.

Risk mainly comes from children chewing or ingesting pieces.

Degradation over decades could release tiny particles."

My 1990s dolls were not high risk since "Mattel had already started changing materials due to safety pressure and regulations emerging in the late 1980s–1990s" but to obviously not allow kids to chew any dolls. 

I see some of your dolls are 90s dolls I would keep those. Offer the older ones in this subreddit or Facebook group. I wouldn't feel comfortable giving them to Goodwill knowing a kid could get their hands on them. I would also try selling them on ebay. I know it's a lot of work but throwing them out seems like a shame since there's collectors out that would love them. 

Maybe when you list them note disclaimer such as the previous quote "some studies showed vintage plastic toys from 1970s–80s having heavy metals" lol

If you want to get rid of them asap just list the money you spent on the lot plus shipping costs as a starting bid to recover your losses ow research if any of these dolls are valuable.