Okay, your setup sounds pretty good to start off with. You might want to get the temp higher on one end of the cage, like say 86-88. These guys hail from Southeast Asia, from some of the same regions as Tokay geckos. Your humidity is good - keep it relatively high. You might want to get a mister - mist mine 1 time a day and keep them on Jungle Bark substrate. They don't drink from a water bowl, so misting and leaving droplets is important. It is probably very dehydrated. Make sure you have wood of some sort in there, like some sort of logs or cork bark. These guys like to climb (although they have claws I'd say they're semi-arboreal, I always find mine climbing/basking high up at night). The bamboo/live plants and topsoil are good. Make sure the hide spots are very dark and very secure - this is a secretive species. As far as heating - you can use just a basking lamp, or you can use a lamp/ under tank heater combo. Just monitor the temps, and keep on side in the mid 80s and the other roughly 10 degrees cooler. Have hide spots on both sides. Concentrate on making it comfortable, not looking for a mate for it. Adding another gecko will not help things at all right now. They are not social, and another animal will introduce added stress, possibly new parasites, etc. And don't put a crested gecko in there!!!!! VERY bad idea - these geckos have strong jaws and they can eat large prey items. A cresty just might look like lunch one night. Don't mix species unless you are an advanced keeper and willing to take the risk.
As far as sexing it, males will have large hemipenal bulges at the base of the tail and pronounced "spurs". As far as handling, try not to handle it or offer it food for 3-4 days. I mean completely hands off. Then late one night sneak in and drop in a large calcium dusted cricket or two. I bet he'll snatch it. Mine are voracious, aggressive feeders and they remind me a lot of little monitors. After you get him settled in/feeding, you'll want to look into getting him deparasitized. But try to get him feeding first. I've had my pair since November and I've just gotten them to the point that they'll eat with the lights still on in the room. These guys stress easily and after being freshly wild caught, he probably just needs to adjust. Give him time, get his enclosure perfect, and then try to feed one or two food items. I hope this helps some. Please don't hesitate to post again if you're still having trouble.

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?.?.? Leopard Geckos (eggs incubating)
1.1.1 Rhacodactylus ciliatus
2.5 Paroedura picta(eggsincubating)
1.1 Paroedura bastardi
1.1 Paroedura androyensis
1.1 Hemitheconyx caudicinctus
1.1 Cyrtodactylus irianjayensis
1.1 Gekko gecko
1.1 Pachydactylus turneri
1.1 Uroplatus henkeli
0.0.1 Hemidactylus turcicus turcicus
1.2 Teratolepis fasciata
Snakes
1.0 Blizzard Corn
1.0 Christmas corn
1.2 Reverse Okeetee corn (1 tang)
0.0.1 Ball Python