Any of these worth bidding on? https://www.auction.utk.edu/APViewInCat.asp?ID=115&CMD=&OwnerID=&SortBy=&VIEW=GALLERY&page=1
I’d prefer to go into my local bike shop and purchase a used bike or new if necessary. You know what you’re getting and and the local bike shop can service the bike with a usual “30 day warranty”. Are the bikes you linked in your local area for pick-up? If not then you have to consider shipping.
I'd take the rockhopper up to 25 if in very good condition, always someone looking for a classic retro ride if you lose interest.