It would be better to keep the temps at "normal human" room temps, something like 72F is perfect, 65F is getting low (ok for a bit, but if you are lower = bad) and 85 is too high. Be very careful with heating pads, we put in one when our heat went out and it dropped below 65F. Crested don't seem to know what is good for them and can easily overheat or burn themselves. I would only suggest a heating pad if you had a thermostat or something to degrade the heat level. Until you get the stands, storage boxes and crates can lift the cage up, we all have those sitting around. You are probably adding to the stress of them by having them so low to the ground. We experienced this with our first leo, he was very stressed by being at knee height. Everyone that walked by him was much higher and, in his eyes, a predator. (Remember that birds are enemy) I wouldn't be surprised if that was the same for a crested.
From speaking to people here and someone that sold cresties for a while, it seems that the best is to separate them as soon as possible - even before you can tell the sexes. Sounds like they are very aggressive and territorial and the theory is that this is the cause of so many captive bred cresteds losing tails. There is some feeling that if you give them a TON of extra space you may get away with more geckos, but they certainly are not as tolerant as leos to each other.
As for hides, something like your leos are fine. We have a plastic hide intended for hamsters (because I thought it was cute), but tupperware will work too. I would stay away from the tape, cresteds seem to eat everything in sight. Think more holes on the sides than the top, but they might go in... be prepared to clean the hides every week... they will poo in them, unfortunately. 
I don't have a picture handy, but we have a really basic set up right now. A 10 gallon (what she lived in when she was little) with a 10 gallon wire mesh cage on top. (Basically makes it a tall 20 gallon.) We like it better than the tall 29 we had been given with the intent to keep her there, the wire mesh is fun to watch her climb on and gives her a break from the glass. (Some have posted here that hanging on glass all day is bad for the geckos and can cause pain and such, I haven't read much about it, save for what is posted here.) We don't have any real plants. We feel really strongly about sanitation after we lost Harvey to parasites. Everything we have must be thrown away or bleached every 6 months. We use paper towels for substrate and have 2 strings of fake leaves and one "tree". Add to that a hide, water bowl, and a CGD bowl and that's it. She gets a light cycle from sitting next to the leo's cage and that's about all she needs. Breeders do keep cresteds in tall plastic storage boxes, but I don't recommend it as why have pets if you don't get to enjoy them?
Hope this helps, good luck.
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0.1 Albino Leo Gecko
0.1 Crested Gecko
1.0 Dear Boyfriend
Departed: Harvey and Spock