Personally i would use the Caddyshack assets and not worry about it. And personally i wouldn't sell it either. How many could you possibly sell anyway? this is not a cheap thing. The Proc, computer, amps, cabling, color DMD, it will be north of $1000. I remember when i bought the Cactus canyon continued it was about $1200 plus I still had to buy the proc. The Bride of Pinball 2.0 was nearly $2000. That's a lot of cake, and most people aren't going to spend that money.
Plus Bride of Pinball 1.x was just *begging* for an update, that game needed it. CCC also in the same boat, as a lot of people didn't thing the game was ever "finished". But with No Good Gofers, most people seem to like the game in it's current format (aside from some score balance and small bugs.) So you're working an uphill battle of taking a game that is already pretty well liked. Your project would need to really push the needle *way* ahead of NGG to get any interest. And i think if it was indeed Caddyshack, that's what would push that needle. Plus you get all the neat quotes and video assets... it would solve a lot of your problems! And if you give it away (to all 5 people that would do this conversion), i'm pretty sure no one is going to bother you.
Look at it this way... Kevin K was going to make 200 predator games, and he was going to get away with it without a license. The only reason that fell apart is because someone ratted him out to Fox (and all Fox did was send a cease and desist, the outfall that followed was because of individual monies paid to KK, and his mis-management of those funds.) And that happened largely because people had paid money to him upfront and were getting worried, then Fox gets involved, the snowball got rolling and he couldn't stop it... Take the money out of the equation and basically your problems go away.