Testing multisig wallet - okay to send to self receive address or better to send to external wallet and back?

Hi all,

Pretty much as the title states. Setup a new multisig wallet and would like to avoid spending extra transaction fees.

I have original wallet A and the multisig is wallet B.

I already sent a transaction from wallet A to B. I was also able to send from B back to A, so I know multisig works with one pair of keys but I wanted to test another pair just to make sure it's all working.

Would sending a single UTXO from wallet B to a receive address on the same wallet B be confirmation enough that the multisig wallet works with that key pair or is it better to send to an external wallet A and back again to B?

I know this is likely overthinking and paranoid. Any thoughts?

Edit: Or is it possible to force all keys in a multisig to sign a transaction? For example - all 5 keys of a 3 of 5 signing a transaction to make sure they all work?