“Sentinel” is just an interface to an API owned by Samourai Wallet. It therefor leaks the fact that you own the outputs you’re watching are probably offline storage (and links them together into one wallet) when you watched them, and your connection details like your IP address and probable physical location.
A single mnemonic seed phrase can be used to derive many different addresses, either via different derivation paths, different address types, etc.
It may often be possible to create multiple instances of the same wallet using different software, but the two wallet applications you've mentioned have nuanced operation and likely use different derivation ...
There are two solutions for the Payment code situation
BIP 47 (extension of BIP 32) and BIP 75 (extention of BIP 70)
Wallets that implement BIP 47
Wallets that implement BIP 75
Wallets that implement BIP 70 and may implement BIP 75
BitPay & Copay
Sources: Coinjournal, /r/Bitcoin, ...