Something you dont seem to have in the bathroom is storage and benchtop space. As a minimum, I would try to fit in a vanity somewhere, particularly if you are targetting families.
Good post Penny. I would add to this, comment that if it was me, I would keep both loos, and if they are indeed right next door to each other, could you take that nice looking basin and put it in the second loo. It seems it could be almost back to back for the plumbing? Then replace it in the main bathroom with another small cupboard style one. It will still be cramped but will give much needed storage.
More shelving on the wall above the loo and you have enough storage for most people.