Keeping my bitcoins safe: any flaws in my strategy? I'm looking for a very safe way to keep my bitcoins. I'm using a Trezor and used passphrase to hide additional wallets in case someone gets access to my Trezor or seed by physical coercion. I'm not interested in recommendations about keeping my seed safe. Hope this strategy can help someone in this forum and would like to get any feedback about some flaws.

My strategy needs to prevent a scenario where there is no Trezor hardware wallet (eg. Trezor is out of business). I checked for wallets that can recover my wallet using my seed and verify myself that it works. The wallets that worked at this moment (October 24th 2017) are Electrum (I used the OS X program), Mycelium (the Android app) and Wallet32 (the Android app).

I restored with Electrum by using the New/Restore -> Creating a wallet -> Standard Wallet -> I already have a seed and then provide the seed with the Extend this seed with custom words and BIP39 seed options checked. And finally provide the passphrase.

Mycelium and Wallet32 are super friendly with restoring your wallet.

Note I currently have only managed to recover my bitcoin wallet from the Legacy Account and not from the Segwit-ready Account. Looks like these wallets still haven't support this Segwit-ready accounts.
The segwit accounts in TREZOR Web Wallet are derived using BIP49.

So far, no software wallet I know support this, unfortunately. I have heard that Electrum is working on it.

However, if you already wrote your seed to your PC or phone to some of the wallets - Electrum, Mycelium, Wallet32 - you should consider it compromised and move your coins somewhere else. Seed is good only if you don't rewrite it to your PC or mobile phone.

Note that Wallet32 is no longer maintained; since it is a regular SPV wallet, it's possible it will stop working with Segwit2x fork. Mycelium should work; as should Electrum, or its Android clone.

Also, other hardware wallets support the same seeds as TREZOR - for example, there is Ledger wallet, that uses the same seeds and the same logic for accounts. So you can rewrite your seed there and you will have access to your coins.

Because I am an employee of TREZOR, I will tell you that it's more wasy to use than Ledger, but I am obviously biased :) but if you have the seed, you can also use Ledger with the same seed as TREZOR.