My rebuttal was to: "We cruised Adventure a few years ago and didn't have a good experience either, we thought it was just us."
And another counterpoint from another poster: "We were on a 9 night in May and really enjoyed it. Yes, it’s an older ship, but we thought the food and service were great."
You can't not use FCC to pay taxes/fees; that is probably what the leftover amount is. If that is indeed the case, you will have to use the remaining FCC (once re-issued) towards another booking.
The most enjoyable cruise ship entertainment I've experienced was on Azamara Journey. Very small showroom (not a theater) and you could sit on the edge of the show floor. You felt like you were part of the show.
You don't need to tell them and yes, she gets her port fees/taxes back (to the credit card that was used to pay) but loses the cruise fare. Hopefully she bought travel insurance to cover the losses.
I thought en route B2B passengers are the last ones off. But, it's been a long time since I've done a B2B, and that was a two segment repositioning on Celebrity.
Not sure where she'll dock, but Marella Discovery 2 (former Legend of the Seas [Vision class]) is on the Havana port schedule for Nov 2022 thru Mar 2023.