With the height, it's up to you, whether u want access without having to bend down. I've used a finer bird mesh that will (hopefully) keep out snakes as well, + the chichen wire if u look at it is large enuf holes for lizards to get thru. On the bottom, try & have something like your colorbond, dig it in as said, & if concreting it in is too expensive u can use a good layer of roadbase compacted to stop them digging out or others digging in. Crickets can't escape over the colourbond either, so u save food.
Any native plants are fine, just make sure they're not too big once fully grown. I've used grass plants as well as they give good shade & can hide. Also plant your vegies & flowers so they can snack at will.
Outdoors wise, if you have your enclosure ready to go for springtime, whatever lizards u have in it will then acclimatise to cope with the winter. Good hides are essential then especially if you get frost where u are.
I used sand (God Forbid:lol
, but grass with sand or dirt, as long as they can dig. With using sand, the drainage (with no base that is) happens naturally & well.
Water supply is really important to organise before u start so you've got any hoses underground - s'pose that's a given. I just used the little horse/dog troughs, but do love the idea of a water feature - there was a pic recently of someone on here's outdoor area & it was spectacular. Happy building!