I have 3 cresties so will try to answer as many of your questions as possible.
My cresties are fed mainly on CGD with the occasional fruit puree. They seem to get on fine with this but when i bought them i ensured that i was buying cresties that already ate it, so if u dont want to feed live food then i wud suggest u do the same. Also to make the CGD more apetising i wud suggest u get the repashy 2 part as u can change the flavour then. I am not sure about the dead crickets, i have seen these to but never tried them. It may be worth getting some to give them a try. However ensure they are not to big for ur gecko to avoid impaction.
My cresties so far have not needed a heat mat as my house is warm enough however if u need one put it on the side of the tank. Floppy tail syndrome is caused if they do not use their tail enough so as long as u put plenty of plants and branches for them to climb it will b fine (or atleast this is how i understand it).
My cresties do not use their hides at all. they hide in the plants in their viv. Cresties need humidity all the time and so u should mist their viv, once a day for adults and twice a day for young cresties. I dont have a moist hide at all, the misting is how they get their required humidity.
For my babies i use a large faunarium and then move them into their full sized viv (45x45x60) as they reach maturity. However if after the move they go off there food for a while i move them back and try again later.
I hope that helps. Anymore questions feel free to pm me and i'll do my best.