Good pics!
I used to keep convicts, and am thinking about getting them again. My son loves staring at fish, and of course he bangs on the tank.. Convicts are so tough, and they have spawns so quickly!
I have never had much luck keeping crawfish with any of my cichlids. I had I wanna say about a 5in. crawfish that did fine for a while, but they always seem to get picked/ate. Just IME though.
Demasoni are great, and so are the labs. Those are my wife's favoirte fish, and the only tanks upstairs are those 2. We had them both in a 75gal before, but I did not get very frequent spawnings, and they were not many fry in the ones that did happen. Once we split them up, I got more often/more fry. If you are not breeding them though, I would say go for it. They look great together, and IME they were both aggressive enough to take care of themselves. The only thing I may think about is the feeding. Most people that I have talked to feed spirulina to demasoni, and nls to labs. I never heard of this until after I split them, I fed them both nls, and they both did fine IMO.
Good luck, take some more pics when you get it all!