Background:
My wife and I are going through the new construction process. The community is a higher-end luxury community. We have two children and my mother-in-law plans on living with us for at least three years to help out with the kids before they start school, but realistically, she may end up with us permanently. Our plan is stay in this house for the long haul (20-30 years).

Main-Level:
We both agree on the option of adding full bathroom (shower) on the main-level. The room will server primarily as an office/study for now, but can double as guest-room, or maybe an in-law suite or bedroom for ourselves in the future. There's also a powder room.

Basement:
The finished basement has a den (which I'm also counting as a guest bedroom) with a full bathroom. This will primarily be used solely as a guest-room.

Second-Floor:
On the second floor, there are four bedrooms and three full bathrooms standard - the Master Bathroom en-suite, an en-suite in Bedroom #2, and a full-bath in the hallway adjacent to Bathroom #3. In Bedroom #4 there is an option to add a full-bath.

The Dilemma:
The cost to add the full bath is a only a small factor, we can afford to have it done. My opinion is to go ahead and add the full bath so that every bedroom on the Second-Floor can have its own private bathroom. I believe this would be a selling-point when the time does come to sell, especially being in a community where it's common for the other houses to be in the 5.5-6.5 bathroom range. Also, if my mother-in-law ends up living with us permanently, she would most likely be staying on the second-floor (while she's physically able to), not the main-level. This means she would either be taking the standard en-suite room, or have to share the hallway bathroom with one of our children. The full-bath option only takes up some empty space (where maybe a desk or toy box would go) as it would be adjacent to a walk-in closet. Also, it would guarantee that our two kids would have their own bathrooms growing up. My wife is of the opinion that it's too much bathroom, we can spend the option money elsewhere, and that the kids can share a bathroom if necessary.

Thoughts? is 6.5 bathrooms too much for a 6 bedroom new-construction house?

Thanks in advance for your opinions!