No one else can answer this question but you since you are the one drinking.
If you will drink (alcoholic and non) more per day than you paid for the package, then it's worth it.
If not, then it's not worth it.
That's not a safe assumption. Always check your table number when you board (it'll be listed in the app once you connect to ship wifi) then if you're not at the same table, go to the head waiter and request a change.
There's no real connection between when you book a cruise and when you book a flight.
Just be careful if you book a business class flight that has a connection. They sometimes will book you in economy (at business class prices) for one of the legs and not tell you.
The solution should be that you need to reserve any chair. Reserve a chair, you get it for 2 hours. You can renew at the end of the 2 hours. But if your reserved chair is seen empty the entire 2 hours, then you cannot renew it.
It's been like this since the new menus came out.
That said the menu that would show for your cruise is NOT the menu for your cruise anyway. It's the menu for that ship's current cruise. So if you really need to see a menu, view that ship's current sailing.