Andrew,
All the boats you have mentioned have enough wood in them to fuel a small brush fire! I would pay close attention to floors and stringers. Check thoroughly around engine mounts and visible bilge area for various signs of dry rot ie:wood splinters, mushy floors, excessive water stains on carpet, especially if you plan on placing any additional ballast in boat. Also check throttle and steering linkages for wear or unnecessary tension. Pylon housings were famous for coming lose in '86-'88 models ie: (skylon or extended pylon.) Look for signs of hull deterioration in vee entry. Excessive beaching or actual fiberglass showing would indicate that boat was handled accordingly and that accomodates all kinds of vibration issues with shaft and alignment. Sorry for draggin' the thread but I dealt with all these problems back in '87 with a Malibu Skier. As far as being a first time boat buyer, keep a monthly budget in mind for upkeep and preventative maintenance. There are plenty of other capable older direct drives in the market, down on the money----you just have to find the right one
Try traderonline.com
Good luck!