-snip- Wallet menu > information will probably tell you how many seeds it has.

The "Wallet->Seed" menu only shows the wallet's main seed phrase, the cosigner's seed can be seen in the wallet file (if unencrypted) instead.

I don't think there are any mistakes made during creation if all addresses across all four wallets are the same right?

Since those are in an "Air-Gap" laptop, do this experiment to make sure:

Open 'Wallet C' and remove its password by setting a blank New Password in "Wallet->Password".
Then find the Wallet C's wallet file in 'wallets' folder inside Electrum's data directory (location), open it as text.
Find the strings "x1", "x2" and "x3" which represent the three cosigners.
Check if 'x2' or 'x3' of Wallet C has a seed or xprv key (should be "null") because if it has,
it can sign the transaction by itself and you've made an error during wallet creation by providing it with a seed or a private master key.