Good boats - a lot were sold as kits so finish is going to range from poor to excellent. The original resin used in the boats was quite water-permeable. Look for one that has been barrier-coated.
Another great boat but with the added caution of a cored hull. I personally would never buy a second hand cored hull as I don't think it's possible to determine if the core is dry without spending many, many thousands scanning the hull. Others will differ (quite vociferously I am sure). Nice, rugged underbody for serious offshore work - will be heavy for the Great Lakes. Some of these were owner-finished as well. Survey carefully.
I would take this over the first two depending on how it surveyed.
If this is one of the British-built ones then it's a serious contender. If not - be careful because I believe these were also sold as hull and deck kits. That's not a bad thing - just be aware of it.
Very strongly built hull but again there is a core and almost all of these were owner-finished.
If all of the boats were in equal states of repair, I would probably take the Tayana first, the Vancouver next, then the Cabot, the Corbin and finally the Southern Cross.
Good Luck !