Hello. Just did the VV Valiant Lady out of San Juan.
I was sitting about halfway across the space of the terminal, inside, away from the ship.
I connected to the wifi...
... did not try to login...
(in android you can set the wifi to "use as-is" and that works best to maintain the connection. It won't let you properly login until you're thru the check-in process, anyway.)
... don't worry about BT, not needed.
If you can connect to the ship wifi as above, the app /will/ work and you will be able to book food and shows.
Believe me, well worth the concentration... I was able to book all of our dining and shows with no issue.
If the app cuts out, just reestablish the wifi, use as-is, and reopen the app.