The on-board price for the 24-hour package is higher than the per day price when buying a package for the whole cruise - usually at least $28/day. Yes, the planner price varies with the various "sales".
The best indicator of a Royal Up win is a charge on your credit card - can come anytime time between bid and after sail away. The B2B process will be detailed in a letter on board.
Very likely, yes, you will need to disembark in Miami.
$14 (without grats) is the limit for drinks.
There are few reports from Rhapsody about Voom but she has switched to Starlink - figure the usual improvement, much lower latency (which leads to real performance improvement for most uses).
Yes, a 24 hour package should be available, but only on board.
The only likely variation of the menus, fleet wide, is for some of the much longer sailings (10+ days). For the others shorter than that, one can assume the menu and the order has been settled - look at current/similar sailing in the app for the menu.
That varies by ship and perhaps even bar. Some of the simpler drinks, like rum and coke, can be as low as $10. The rough math whether the package makes sense financially depends on your drinking pattern - if you know for sure you will drink more than 5 alcoholic drinks each day, get the package.
It may vary by cabin type but usually the plug there looks like a US style plug but has small holes next to the spade slots to allow a European plug to also be used.
Yes, but on some ships they don't post them (and other info) until on board. In that case, as mentioned above, set the app to the current sailing to see the menu.