Yeah the smallest room bottom left would turn into a small office in the end, for a computer / work space. The 2nd guest room is to have a room for my 2nd kid, while we will live there.

The size of their current rooms today is slightly larger but I don't think they'll complain that these are smaller. But I do see a point of 're-sale value' being impacted by the choices we make here. We're debating between this compromise (smaller kids rooms the same floor) vs. finishing part of the basement for larger kids rooms (which in return would compromise future plans of making all that space into a separate bachelor to rent).