BIP 137 which could be standard for sign message with SegWit address isn't adopted by anyone and each wallet have different standard.
So if you sign a message with Trezor web interface, you also must verify it with same application. This applies for all wallet, unless 2 or more wallet use same standard.

My suggestion are :
1. Sign a message with SegWit address using Electrum, so other people could verify it easier (since they just need to download Electrum)
2. Wait until BIP 137 or other standard widely used by majority of wallet which support SegWit