Seems you answered your own question. Yeah, anyone can create Mickey Mouse NFT but unless Disney officially releases it themselves, people will not be (as) interested in buying.
Takes like 5 seconds to check Disneys Twitter feed or blog. If they haven't said anything, they haven't released anything.
How do you verify that Apple has released a new phone? You don't, you hear from Apple that they released a new phone. Why would it be different with NFTs?
I'm pretty sure someone like Disney will have their wallet public on their website. They'd also likely own an ENS domain and sit all their addresses behind that, for example waltdisneyco.eth or something along those lines.
Isn't it as easy as an official Disney representative announcing ownership of the wallet and signing a message cryptographically using their private key?
