How about turning the dining into a study and close the entry to the study off and re-work the back hall by the guest room to have a door there and create access to the bath and have another bedroom instead? I'm thinking since you said you have a large family.

Or you could make it less open and use it for a play room.

What does your family like to do? Would it make sense to set the dining room up as a game room? Or a library?

FWIW, I'd be tempted to either move the door to the guest bath to the hallway or add a second door there, because it would make that bathroom easier for guests to access, and it would put a guest bath on the first floor in a more public area (there may be times you'd rather not have guests in your mudroom).

I'd be inclined to put the TV in the study (unless you plan to use that as an office). My kids hardly watch TV on the TV anyhow (they prefer the tiny screens of their little devices).

I'm wondering how anyone can pick a floor plan when they have these sorts of questions. Seems to me that they would have the answers before picking any stock plan. Or use a design professional to design a house based on their needs and wants.

Just seems so backwards to me, leading to endless changes and doubts.

Good luck with your project.