That bowl is pretty enormous. I'm sure it's fine, but wow! You might want to look at cluttering the cage up a little more until he's bigger, just for security. Hot glue would work for the tree, but remember you'll need to be able to get in the crevices to clean it (BPs love pooping in the hardest to reach part of the cage! You might want to seal the base of it with silicone if you decide to make it a permanent fixture (keeping him elsewhere while it cures, of course).