Jamie T

In theory the Key and the Suites terminal area are separate.  
You could just approach the Suite elevator with your set sail passes while the kids keep theirs in their pockets.  They'll likely assume you are all in the same suite.  Once upstairs in the suite terminal area they check you in on a tablet.  Generally speaking they have you find a seat then follow you to your seat to check you in with their tablet.  They might say something about the kid's Key boarding passes at that point but probably not. 
They have every right to escort your kids next door to the general area where Key will be allowed to board right after suites but I'm guessing they won't.  If they do then you can go with them.  The difference in boarding will only be a few minutes at most.
If you have your set sail pass in app you are done.  No need to do the TA paperwork.  It never hurts to have a paper copy of your set sail pass which I prefer anyways.  Until you get your cards on board if you want a drink you have to hand over your set sail pass to a bartender.  It's a lot easier to give them a paper pass rather than your phone.  Plus if your phone dies or your drop it having a paper set sail can be a stress saver.
This morning coming off Oasis I joined the self-assist line at 6:15am.   They started letting us off at 6:42am.  I was outside hailing my ride share at 6:48am.  I was through security at the Fort Lauderdale airport with bags checked by 7:31am.  Ride share cost was $35 plus tip but that service wouldn't fit six people.  I assume you are flying from the Miami airport which is closer and will be cheaper.  A private transfer for six will probably work out a lot better.
The beauty of getting off the ship early is that the terminal traffic is very light.  By 8:00am it's busy.  By 9:30am it's chaos.  Even the bus transfer vehicles get caught in the grid lock.  It can take 30 minutes for a vehicle to go halfway around the terminal road right in front of terminal A.
I'd suggest using the first suite escort off the ship on the final morning to beat the crowds.  

I believe that I wore shorts in the MDR for dinner on night one during my last sailing, but I was also in a nice t-shirt and my shorts were khakis (not gym shorts). As been said, the dress code is suggested; not enforced.

This is great info, thank you both. I just got off the phone re-booking our UDP (price decreased by $70 since we first booked?) and I asked the rep about the dress code in the MDR for our Jan 5 Oasis sailing. He told me "no shorts"...at all...not even for breakfast or lunch...same applied for specialty restaurants. 
Now, let me also say that I worked for RCI on several ships for 10+ years, so I know that what corporate states is not necessarily what the ship will enforce. Heck, many rules differed from ship to ship. It all depended on the Hotel Manager and how relaxed he or she was. 
 
Again, thank you both for the info?