Ah, I just have an exoterra. Sorry for not clarifying, whoops!
I did get long bits of velcro to try next just to see, hopefully that'll help. So far the suction cupped items havent posed any problem, he sits/naps right on top of them. He's just worming his way behind the background and I don't really like him doing that. If the velcro doesn't work, I'll have to explore a more permanent solution... which isn't the end of the world, I just had ease of cleaning in mind.
And yeah! I definitely have upgradable parts for him. His perch is a somewhat skinny piece of bamboo, but I have a larger PVC one to put in when he can no longer use the bamboo.
Very beautiful setup, by the way!