Nice work Sherlock! I think the “ally” line works the best out of those tests.
I agree Rey’s “please” sounds unnatural and added in though, same with the added Rey and Finn lines at the end of the other 3PO lines. And even on paper, Rey doesn’t know Jannah & co. can help them so why would she say “please”? I think it works better if she just plainly states their business, showing some trust but also being a bit blunt, then C3-PO helps by remarking they’re “allies” before Jannah decides to offer help.
You’re right, the Threepio remark does make the “please” redundant.