I have both my crestie and leo in the living room, I usually stay up pretty late and they still come out when I have my living room light on. They kind of adjust to house lights being on and it doesn't affect them, so long as it's not shining into their eyes it should be fine.
I would not stress about him not eating anything right now. He probably has eaten a bit of the repashy, you just haven't noticed it missing. Mine ate little bits of it when I first got him now 2 weeks later he licks his bowl clean and I even spotted him drinking from his water dish last night. Mine still has not eaten any roaches, he's interested and the hunting response is there, he just won't eat them. Some cresties will just not eat bugs at all, while others will. Don't stress, try to stay calm and let him do his thing for about 2 weeks or so. It's easier said than done, I know.