Migrate old Bitcoin Core wallet to Trezor I have an old Bitcoin Core wallet, and recently bought a trezor.
I wanted to use it, but I am unsure how to migrate it. While I can access it with my password, I do not know how to find its 12-word recovery seed (If ever there was one).

Do I have such a recovery seed?
Is there any other way I can migrate my wallet to the trezor? (Other than creating a new wallet and transferring funds from the existing one to this new one)
Can a Trezor hold several bitcoin wallets simultaneously? (Suppose I created a new one, and later discovered I can also access the old one through it)
Do I have such a recovery seed?

No. Bitcoin Core does not use mnemonics nor is the seed exportable.

Is there any other way I can migrate my wallet to the trezor? (Other than creating a new wallet and transferring funds from the existing one to this new one)

No. The only way to migrate is to send a transaction that transfers your Bitcoin to your Trezor.

Can a Trezor hold several bitcoin wallets simultaneously? (Suppose I created a new one, and later discovered I can also access the old one through it)

No.