First .. EXPs are almost always accomodate (if you meet the checkin requirements). Technically the last persons who bought their ticket will be the first to be removed (denied boarding) should they not get sufficient volunteers .. but basically EXPs are pretty much accomodated.

How soon is this flight? Normally when there are 4 unassigned seats on an MD80 the system will stop automatic upgrades by tier clearing time .. You indicate there are 7 unassigned First seats .. perhaps Coach is oversold THAT much so this Yield Management has increased the Gate Control First seats from 4 to 7 . or you could be beyond the 100 hour window (since you don't mention time/date/flight).

At 99 hours I would check to see if any seats open .. those would be EXPs above you on the list and they may open up an Exit Row seat . so grab that!

I hate to say it but with FLL and cruise ships at this time of year .. oversold is very common. I would probably consider heading to the airport WAY early (planning to catch/standby/upgrade) on the full prior FLL-DFW flight. If you are on the noonish flight that is heavy cruise pax.. try the earlier one at 9:45am which typically is before cruisers can get off the ship and to the airport!

Having NO assigned seat is a bad situation. BUT being EXP you will most likely be accomodated tho possibly center coach seat. The upgrades will probably be Gate Control when flights are this full/oversold.

AHHHH . the fun of cruise time in Florida!

BTW .. are you traveling alone or with others? Alone will be simpler to change/upgrade. Also if you are checking luggage .. try and standby/check on the earlier flight .. Forget about the Kiosk checkin . use the First Class checkin line and see what they can do.

On prior cruises I normally would book the noonish flight . but rush for the earlier one. They have normally been thankful to get a seat on the oversold one .. and I have gotten the upgrade on the earlier flight.