If you really need 4 of you on at the same time for the whole cruise then buying pre cruise is the way to go. You can supplement with the free days you get as the D perk on board. If you only need it on sea days and can live with sharing, then you can fall back onto using the D perk on board only.
Don't change your usual plans (use D+ days at the start for a couple of days and the remainder at the end) other than to buy the $10/day package from AT&T in the port(s) you think will really need it (when you don't have Voom on board).
Cruisedeckplans is fairly accurate with its info and pics - you can confirm yourself. BTW, she didn't get the full AMP like some of her sisters - mostly just the slide added.
A whole swath of deck 7 on Ovation is marked as obstructed leading to usually lower prices - don't ask why, just bank the savings. Also, folks' impression of the obstruction, even on deck six is about as subjective as the food in the MDR.
RCI doesn't have uniformity across their Q class ships as to which are considered obstructed, so trying to figure why one is while another is not just leads to frustration.
Assuming you looked on the UK site, look on the US site as well. If still available there, good chance the UK one will become available again or make arrangements to book via the US.
Yes, though don't expect the actual price to go down much, if any, for such a close in sailing. Whatever the price, it'll likely still be lower than on board.