Most shark eggs being sold at lfs's are banded cat sharks. Essentially its a bottom dwelling shark. Having a crushed coral substrate could easily scratch his underside. If you can, sand would be much better. Becareful though, some of the sands, particularly the black tahitian sand are just as sharp.
It could do fine in a 65 gallon for some time. I'd be hesitant on if it could go over a year though.
I've never hatched one, but have been told that it can take awhile for them to start eating and maybe difficult to get them to start.