Have you thought about using CEXes instead of Bridges? You could just deposit your BTC, and then on the withdrawal process, you can choose the network you want to withdraw your WBTC to. I obviously wouldn't recommend storing WBTC for the long term though.
For a higher fee, there's also those non-deposit exchanges like eXch.cx which have started advertising in BitcoinTalk through their own signature campaign. Third-party risks are probably the same as Bitstamp and other centralized exchanges, but they act like "bridges" and there's no need to go through KYC.
Plus OP, why not hold the actual base coin/unit for that blockchain instead of holding Bitcoin as an IOU in another blockchain? It's better to hold the shitcoin than holding an IOU in a blockchain of a shitcoin.