Fullmoon ---- we live near Oakland. We've been to Cabo, Cancun ---- but our regular visits to Mexico are to Puerto Vallarta and we often stay for a week in Nuevo every other year or so. We've been to Vidanta (twice), Villa del Palmar Flamingos once to stay (but many times, as I own there and our Annual Meeting is held there).
We've also been to Villa del Palmar PV over a dozen times. It sounds like you are also a Villa Group owner, with mentioning many of the properties.
I know zero about Acapulco. Can't comment on that.
To address your issue regarding the Grand Mayan. We do not own at Vidanta. We stayed at the Mayan Palace for a week recently (we like to get all over the place). We are staying at the Grand Mayan Nuevo in early December (right after you) ---- we did explore the Grand Mayan property while at Mayan Palace, but were not allowed to use the pools/gyms, as Grand Mayan is higher on the tier than Mayan Palace. We walked through there daily and ate at restaurants there and walked up the beach from there, to get off property.
From our experience (and we research intensively like you do), the Grand Mayan is FULL of families with kids. It would be the same at any Grand Mayan. Not just Nuevo.
It was very loud there (and active with the little ones, from about 5 to 15) in the water areas, the beginning of December. We met people who were staying at the Grand Mayan who wanted some relief from loud kids while swimming, who moved to the Mayan Palace pool.
We are staying at the Grand Mayan in early December to do a "scouting trip" for my grandkids next year (8 and 6 now).
All the activities you want are available on Vidanta property BUT ---- as you know ---- it is complicated and time-consuming to get off property, as it's massive and they would prefer to keep you there. As "veterans", we know how to do it, but keep in mind that it may be a little frustrating on your first try, until you get "the lay of the land."
As above, since we live near you, our choices are often formed by distance and price of airfare. We fly to Mexico (PVR --- which serves Puerto Vallarta to the south and Nuevo Vallarta to the north) on Southwest Airlines or Alaska ---- so we always go to Vallarta.
The Mayans (Vidanta) will be similar in both areas.
Hope that helps.