The plants capn recommend are deffently good with the lighting reqyirments of an axolotl if you wanna keep other plants plants try to find a way to suit both plant and axolotl requirments, like I used have lilys that grew out of one of my old tanks and they had good lighting on them however the floor of the tank was dark since the lilys provided shade, and for substrate I use play sand, it's super cheap, one 50lb bag is bout $4 over at home depot, if your Gona use play sand make sure to rinse well, I rinsed my sand out for bout 1 (for 25lbs) and also while you do that look through it and feel around for rocks, sticks, clutter, I have yet to encounter any but I keep an eye out just to be safe, and once you do this and put the sand in your tank give it a day or two to settle. Hope this is helpful.