Besides the obvious, I see no reason not to.
Flame angels are deep water fish, and should only prefer to eat sponges. They're predominantly carnivores. They've been known to nip at the fleshier of LPS like Trachyphyllia. I wouldn't trust them with small shrimp like Thor. It might peck at some softies like Xenia.
Leopard puffers (Canthigaster, right?) should be somewhat safe. I wouldn't dare to keep them with LPS, clams, or shrimp.
The reason it says "with caution" (I'm assuming DFS LA here), is because they can live in certain reef tanks, but not all reef tanks. For example, you could probably keep a leopard toby in a softie reef, but not anywhere near Tridacna.