>>1) The potting soil that I must put in their "caves" is regular potting soil good?
>>2) Paper towling is good to use as substrate? Nothing better I could use?
>>3) I know two males cannot co-exist, is it healthy to have two females together? Or is it better to have them alone?
>>4) A food dish should be used for placing crickets and other food items? Is this the best way?
1) You dont have to put potting soil in their cages, you can have vermaculite in their "humidity hide" you can make one by using a glad ware container by flipping it upside down and cutting a hole on the side of it so it can get into it, and put the lid on it and put paper towels on the lid so that you can get your humidity, that is the easiest way for beginniners.
2) you can use paper towels, tile, roughed up linolium for a substrate but i dont recommend sand due to impactions.
3) yes your right two males cant be in the same cage but 2 females can unless one of them is bullying the other one. But if you get them from 2 different places you have to quarantine them for 3 months (keep them in seperate containers)
4) You can use a food dish to put mealworms, super worms, occasionally wax worms, or crickets in. If you are going to use crickets then i either suggest pinching off their legs so they cant get out, or let them walk around and get eaten but take them out after a half an hour because they will eat your gecko.
Heres my site for leopard geckos care:
My Site
-----
[
