Allure has most of the perks, including access to the concierge and included internet access.
Not sure what you wanted to use the concierge for, but, they're mainly helpful for making reservations and such.
Most of what you're looking at is marketing hype. If you tell us the ship you booked on and what kind of suite you booked, we can give specific information.
My beef with Roatan is the never ending spammers hawking tours on the on another social media platform. Other than that, the tours felt safe to me. I don't think I would wander around on my own though.
This may be particular to your version of MFA. Ours (Duo) allows you to input the code that shows on your phone and you do NOT need internet connectivity to use the code.
As for the OP we used Teams on our recent Enchantment cruise. It worked but we did have connections dropping all too frequently.
We often travel with friends who are from Europe. Before the cruise we ask what kind of change they would like. We're happy to get the Euro's. Perhaps you can ask someone on your roll call if they would be willing to bring you some change?
I think you're right to think about this. I did it for a recent booking, although we had 4. The extra space and bathroom we're welcome. (I did this for my sister's family) One thing. They never used the connecting door. (Oasis) They liked the privacy of having that closed and the balcony divider open.