I just received my Trezor and I wanted to go ahead and send some Bitcoin's to it while I figure out how to work the Monero Trezor firmware by NoodleDoodle. Is it possible to import the private keys I create with the main Trezor firmware now with the Monero Trezor firmware I install at a later time?
Installing a new firmware on a Trezor, it won't be possible to import private keys.
Because of the way Hierarchical Deterministic wallets work, a new seed and wallet will be created (with its own set of private keys).
Therefore, you should temporarily transfer your bitcoin to another safe offline device while you set up the new firmware and seed and make sure you have back ups for the temporary wallet.