I wanted to experiment with the testnet options, and used the Rinkeby faucet for test Ethereum, but they never showed up on my Trezor (checked over the past few days). The transaction was successful (almost three days ago), and the address was correct. Am I misunderstanding something with the testnet, or does it not work with some options?
Your TX ID won’t be needed. Even though Ethereum has several testnets (Ropsten, Rinkeby, Kovan), Trezor Suite supports Ropsten only. As you used Rinkeby, you won’t be able to access your tokens by using Trezor Suite. For other testnets use MetaMask, MyEtherWallet or MyCrypto.