Allegiant Air will take you as a JSer
We do not have a formal agreement with Miami Air, but are in the process of forming one. Miami Air has scheduled flight from MCO and MIA to San Jose, Costa Rica. The charter/supplemental does not allow others to jumpseat as a rule and it is near impossible to count on it as there is no schedule.
Allegiant takes unlimited jSer, both pilots and F/As to ride in the main cabin after dispatch approval.
AAY now has scheduled service from Orlando/Sanford (SFB) if that helps.
I believe you will not do well as a commuter with Miami Air, given their schedule IMO.
Good Luck,
Jeff