Unless it's a specific category GTY (like 4D) don't pay anything extra for any other balcony GTY. That may even be an IT glitch as Q class don't usually have more than one general balcony GTY.
Welcome to CC.
That may depend on the cabin but it's probably pullmans for guest 3 and 4. Look on a site like cruidedeckplans on any Radiance class ship for your or similar cabin for layout.
Welcome to CC.
The vast majority of RCI's profit comes from on board sales (hence to the ton of marketing emails) - you don't need any of them to have a wonderful cruise - you have already contributed to RCI's profit with your suite.
If you have set dining, the app, set to the current sailing, should list that. On Liberty, some reported getting 5:30PM for early seating which later changed to 5:00PM. Assume 5:00PM with no other changes for the rest of her time in NJ.