With what you've had, taking into account that they are probably minimally extreme projects... This also assumes that you can check and ensure that games all have boards in them.
Black Knight 2000 - $700ish. For reasons that I'll never understand, BK2K seems to have a very high secondary market for it, and a complete and working game will bring easily $1500 or more. Besides that, you said that you enjoy fixing machines up and you want this one, so I would give it a bit of an extra bump for that.
Bad Cats - $500ish. Another game with a strong secondary market. Looks like stuff is sitting on the playfield glass, so I assume what is underneath is mostly okay.
Monday Night Football - $400ish. Game does not command a high premium, rarity means parts aren't worth much but will be hard to replace to fix.
Hurricane - $400ish. Probably the least popular Williams DMD title, and that's saying something.
jokerz - $300ish. I've seen nice working ones sell for about $800 relatively recently, so anything more just doesn't seem right.
High Speed - $350ish. See Whirlwind below, but know that High Speed is a little less popular than Whirlwind, so your final sale price would be lower.
Whirlwind (badly worn playfield) - $600ish. This one is tough - Whirlwind had a playfield repro recently and I believe they are making more. It also had a plastic repro. Playfields and plastics on them are always blown out, so replacing / upgrading those doesn't make a huge difference. If everything is there and good, it's a $2000+ machine now. Parts are abundant.
evel knievel - $250ish. There were lots of them, but it's older and doesn't command a huge premium.
If you're going to make a group buy, I'd suggest going down at least another $500 overall so you'd be looking at $3000 for everything, or $375 apiece. I don't deny the people claiming lower numbers (hell, usually that's me!), but games like this do have a floor because you could always part them and sell them if it comes to it. For instance, a blown out but complete Hurricane playfield and boardset will put you back to your $400 level easy. That's where I tried setting my numbers.
Good luck! I'd love to rummage through 100 playfields just to see what is there