Lilly did her first charter at 7 weeks. You didn't say how old the baby was, but pack and play size gives a tell. We never bothered with life jacket.

We had a seat like that also and with the boat motion it had a large range of swing, almost too much as it got in the way of people moving about. As lilly got older I would rig a bosun seat from the clew on the jib, that was great fun.

It was a non issue as she would sleep at most restaurants at night while we ate. Something to cover up to prevent bug bites is good.

We used the cooler aboard for years as a "pool", until later we kept an small inflatable pool in the cockpit (adults enjoyed that also).

Do not plan on buying diapers in BVI, even with the babies born there we had a hard time locating diapers.

We just put some luggage in front of her berth in the unlikely chance she would roll out, was never an issue.

A lot of sun protection at the beach.

As the kid gets older something to think about is not all beaches are created equal, many have small drop offs, as adults we don't really notice. Pirates is probably the best beach for small kids.