- But I can't figure out the sending address by looking at the blockchain
Your sending addresses are:
1Q6Uy4Az29YSJcGjAMhHcVWgT9fCkrp1AY
1AMuQGdQ6Hq1dgubs2Yvy2x9W6tgdSPja8
- Nor can I find it on Trezor since I don't have a static public address
AFAIK: You will have to take the mnemonic seed, derive the addresses from it, find the two that I've mentioned, then take their private keys and import them into counterparty. You should check the NVO sheets to see whether your addresses have already received tokens or not.
- I suspect the tokens won't come back automatically to me on Trezor, and even if it did I couldn't see the token.
People do not understand the concept of wallets. A wallet does NOT hold any coin, tokens or whatever. A wallet is merely a collection of keypairs. Trezor does not support counterparty, thus your tokens will not be visible from there.