MMcBride

We've done this successfully. Just talk to the maitre d' on day one with your request. Be prepared to wait for your table occasionally (usually pretty short) if you have My Time dining. 

Yes, to the first question and no to the second, the head of the dining room would be available. Your head waiter might be elsewhere as sometimes they work multiple jobs on the ship. 

Yes and yes.  Get to the MDR EARLY upon arriving.  If you're in a suite, contact the Concierge for arrangements ahead of boarding.
No guarantees, good luck!

Yes on that Thanksgiving sailing it did fill up, they redirected to parking a terminal J (i belive) and provided shuttle busses back to A.  Talked with a number of folks that had to do this.

1st holiday cruise! Something to look forward to!

I have never personally experienced it, but yes it does. They will direct you to another terminal for parking and provide a shuttle to Terminal A if it happens.

They're starting to bring back some onboard extras that they had stopped offering due to COVID.
Old article about the Sip.Tour.Brunch: https://www.royalcaribbeanblog.com/2019/12/19/spotted-sip-tour-brunch-galley-tour
Basically this is a meal and a behind the scenes galley tour.
The sushi making class has also shown back up for my upcoming Oasis cruise.

In our experience, the check-in wait times (after you are inside the terminal) can vary quite a bit and the appointed times probably won't be checked by terminal staff after the first couple appointment times. For our last cruise on Allure through Port Everglades in Sep, we had a noon check-in time and entered a sizable but generally moving line outside the terminal at about 11:30 AM.  When we reached the door (at about our check-in appointment time), there were no signs for appointment times -- they just wanted to get all guests processed as efficiently as possible. 
Inside and after the bag scan, we entered the main room with probably two dozen small lines you could pick from to be checked in by staff using tablet computers.  This is where you arrive at the luck-of-the-draw stage of checking in.  You can't know which passengers will have problems with their check-in information, or which staff's tablet will go down preventing a line from being processed efficiently.  To my wife's (minor) annoyance, we each entered a line next to each other.  This turned out to be a good thing because one of the lines experienced an appreciable delay compared to the other.  The one in the delayed line (I won't say who) ducked under the rope and we merged into a moving line to marginally speed up our check-in. 
In the early days after the restart and before passenger numbers returned to normal levels, we breezed through check-ins.  We also recognize that each terminal's check-in layout and process is a bit different and some are better equipped to handle a larger stream of passengers than others.  It may also be that our last embarkation day was during a partial network outage at Port Everglades that affected many of the check-in staff's tablets.
All things considered, we will go with the flow of check-in even if it is a bit choppy so we can board the ship sooner.  We like to nail down some reservations and stop by our muster station right after we board and would prefer not to do this later in the afternoon.  Then we enjoy our first beverage and, mentally, our vacation really kicks off.   
What we will do for our next cruise is actually check in on the earliest date possible (45 days form sail date) and not dilly-dally with the check-in.  Nab an early check-in time right off the bat so you don't feel compelled to re-check a bunch in an effort to snag an earlier appointment if you can.
Happy Cruising!
 
 
 

Short answer is yes. Even without the whole vaccine and negative test aspect, check-in lines allow the staff to verify that things you did before hand are actually in the system and tied to your set-sail/sea pass account.
For example, on our most recent cruise on Allure, my mom's passport number and photo did not appear on their end even though the passport had been in the system for almost a month and the picture was saved and showing in the app 24 hours before boarding. A simple glitch that was only caught because of the line.
Fortunately, as others have said, the lines move through much faster now thanks to the app and the general reduction of physical paperwork so you shouldn't be in line for very long.
If you have a concern/preference about avoiding lines, I'd recommend one of the last check-in time slots (like 2:30 or so?) as a majority of the people getting on love to get there between 10:30 - 1:00.

Yes, you still have to check in at the terminal. Checking in via the app will save you time by inputting your documents and linking a credit card ahead of time.

The selection of the arrival time is to avoid massive lines/crowds.  The ability to add your paperwork/documents and photo ahead of time also reduces check in time/lines at the pier.  Yes, we must show original documents at the pier, I don’t see a way they can avoid that. 

When we last boarded Harmony of the Seas in Port Everglades, except at Security, there weren't any lines at all. Once you cleared security, there were so many open counters that no line was even able to build. We just had to show the Set Sail pass, they checked the passport and the uploaded picture and that was it, probaly took about 20 sec. max per person and. Once done, we were directed directly to the Gangway.
From stepping out of the taxi, dropping the bags, through security and documents check until stepping onto the ship I'd say it was less than 15 min. total. The check-in process is perfectly streamlined.
Now, at other ports where they don't have their own terminal and visit regularily, the process might take a bit longer.