I'd skip the hardwood and linoleum. No matter how well you seal it, sooner or later, moisture is going to get somewhere... You can get 1/2" pvc sheets at home depot for $55-$70 per sheet now I believe, in black or white. That's what I'd go with. Cuts easy, it's light, and easy to work with. 24" seems kind of high for a ball python enclosure, especially if you're heating with an RHP. The closer they are to the surface, the better and less power they need to use to maintain the temps. I don't think I'd go higher than maybe 18". I think 14" would be plenty high enough, but that's just my opinion.

For venting, could you just cut some slits in the back of each cage?