Personally, i know that every great expired domain is very powerful.
I have a niche website with 14 - 16 expired domains from different niches, and they're helping out.
However, this totally depends on how powerful the niche is, if you're going for a hard keyword, then you should approach the link building with strategized plan.
Buying niche related expired domains, then using different and relevant permalinks, reviewing four products (or more) each and doing silo link building.
Goodluck and success.