Can MEW (Myethereumwallet) secured by a trezor participate in token distributions like MEW secured by a UTC or Private Key? Can the MEW secured by a trezor call arbitrary contract methods and export private key through a smart contract? Please help. One of the ICOs I want to go for requires that from a wallet and I am not sure if MEW with a Trezor is safe to send the ETH from.
Yes, technically since the key is on your Trezor, even on a hacked or phished version of MEW they could mess with the tx but wouldn't get your keys.
Yes, a trezor is SAFE for all of these uses. You are required to own access to the private key of the address in which you are executing contracts from (for most uses). Since your key is inside your Trezor (therefore owned by you), you can use MEW with your trezor.