I think the poster was alluding to the fact that many have reported previously their bids being cancelled whenever there's a notable modification to the booking, like a cabin assignment.
Welcome to CC.
Odyssey, as part of Q class ships, has some of the highest ratio of balconies to insides/OVs so it's not unusual to have balconies priced lower (especially GTY) than an inside or OV.
You just look at all the decks, like you would need to on most other sites- the cabin types are easy to see. There are OVs in the front of the ship not just the sides.
Planner items become available at different times - keep checking. Spectra in 270 is the only show which takes reservations. The free versions of Ripcord and Northstar can only be booked on board at certain times.