Hi! His colour seems fine to me. As we've mentioned in another thread, they can and will change it pretty dramatically.
The ivy is good, it gives hiding spots and something to climb on. You do definitely want more things for him to climb on though, mine is almost never on the ground. I can't see any problems with lego, all sorts of other plastic goes in peoples vivariums with no troubles, but I have never tried it myself. Definitely make sure there is no chance of a piece of lego coming off that is small enough for him to swallow.
Here's my go-to article (by Johnny O. Farnen, who posts here occasionally) about what kinds of woods you can use in a vivarium and how to treat it if you want to go for more natural perches than lego:
Caudata Culture Articles - Wood in Vivaria