Jungle mix should be good. I use it at the very top of my layer of topsoil, basically just for looks. My advice would be to use normal store-bought topsoil (ORGANIC - no chemicals), since it is way cheaper in quantity than jungle mix, and they like to burrow in it on occassion. I also use some moss, but only in a couple spots in the tank, because I have heard bad things about how acidic some can be.
He should gladly take chopped up nightcrawlers, just don't overfeed him, as tigers never seem to want to stop. During times when I have an animal I want to fatten up, I gradually feed them more and more, not too much at first. I feed them a little more frequently than I normally would with the healthy sized ones, such as a little bit each day. Im sure he'l eat waxworms too.