MIA or FLL Transit and Beach Stop
 

I'm thinking of a couple of options to travel cheap ATL-MEX via either FLL or MIA in May.

Option 1) EXTRA NIGHT IN MEX: Fly into MIA on American Airlines coach on Wednesdayarriving to MIA at 6:39 pm and one international MIA-MEX on Internet departing at 08:10 pm. A change in terminal is likely from D to C (or F?) Does Interjet allow me to print international boarding pass online within 24 hours of departure? Do I need to check in with passport at Interjet counter or can I just walk straight to the gate (saying if they allow online boarding pass printing)? Will I likely make it in 1 hour and 40 minutes (between domestic arrival, check-in, security and international departure gate) with hand-luggage only, assuming AA flight arrives on-time?

Option 2) BEACH STOP: Fly into FLL, with a 4 hour 50 minute layover, then FLL-MEX, both on coach tixs on jetBlue on a Thursday (08:49 am arrival, 01:40 pm departure), no checked bag, travel solo. I also plan to exit airport to visit a beach 25 minutes away by Uber (each way). How long can I spend time at the beach that allows me to arrive at the departure gate without trouble? Does jetBlue have kiosks for self-service international check-in with passport or do I need to present one at their counter? Can this be done upon arrival or do I have to wait to do so within 4 hours of departure? I estimate a safe bet would be spending time at the beach 90 minutes max, assuming fair lunch time traffic from the beach. Would it be worth it?

Which itinerary would be more realistically safer? Any help/ideas would be appreciated!
Edited: Chatted online with Interjet. Rep said not enough time. Thus, I might do beach-stop option then.

Bumping for response :-)

Uber is best bet, as public transportation sucks.
I would be dropped off at B Ocean resort or the next door Marriott, so you have a place to dump a bag at bell desk. And you can use the pool shower to rinse feet from walking on the beach.
I would think you are good heading back at noon. You will have already shown passport on check in. Security lines usually aren't bad.
One thing to consider is the 17th st causeway bridge. While it is very high (55ft.) and does not open all that often it can open on the hour and half hour. If you hit a bridge opening, that could add 20 minutes to your commute time. This time of year, you will have large sailboats headed north.
But as long as you are through there before the hour or half hour, you are okay.

Not sure what advice you are looking for. It's 5.6 miles in either direction to the beach. You can grab a cab or uber and go north to Ft Lauderdale Beach and be dropped off at B Ocean or Ft Lauderdale Beach Park. Its 5.6 miles, or about 15 minutes.

You can grab an uber or cab and go south to Dania Beach and get dropped off at Dania Pier and its 5.6 miles or 15 minutes.

So, you have to decide how much time you are comfortable with at the airport and what you want to do at the beach. Either way you go, its a beach. Sand, water, etc.

Jet Blue probably wants you to check in within 2 hours of an international flight. No one can tell you whether you need to heed that advice or not. That is on you.

So, if you arrive at 8:50 and get to the curb to catch a cab by 9:15, you will be at the beach at 9:30. Then sit on the sand and stare at the water until 11 if you want and grab an uber back. Ubers might be more easy to find going north, but either way its doable.

FLL isn't a great airport to spend a lot of time in. Personally, I would grab a rideshare or cab and go have a nice breakfast at Grandpa's Bakery in Dania. Pig out on some serious home made pastries and hearty breakfast/lunch foods, and waddle back to the airport for my flight/nap.

Not sure what else you are looking for? How much is 90 minutes at the beach really worth to you? We can't say. It's not worth that much to me.

Except FLL would be a stop. The OP would have already checked-in in ATL. So it is just a matter of going back through security and getting on the plane.
Forgot about Dania Beach. A more natural beach for sure.

Thanks to everyone who responded. I now have some ideas... You're totally awesome!