Using High Authority Expired Domains

I have a large selection of high authority non-spammed expired domains all within a particular niche.
All of the domains including my money site are in the same niche.

Would you say it would be best to either:

1: 301 redirect them to the relevant areas of my money site.
2: build out the expired domains to how they were and link back to my money site.
3: a mixture of 1 & 2

Interested to hear your thoughts and any experience in this method.