The societal hatred and greed had become pathological. The Seminoles would have to return runaway slaves to the United States, and stop raiding Georgia. No weapons can be sold from Florida to the tribes in America, and no tribal warrior could be given refuge into Florida. The Spanish would have to give up claim on all Florida west of the Chattahoochee River.
The Americans in the south are still going to raid and squat into the remainder of East Florida. IMO the early filibusterers (try to say that word and not laugh) are going to invade, pick a fight with the Seminoles and Spanish, rob, destroy, kill, and then act like they were the aggrieved party. The southerners might even fabricate the matter entirely. If there is any American interest in another piece of Spanish property the southerners will use the excuse to invade and destroy the Seminoles.
If Spain cut a deal, then put the stick about, and if the Seminoles swore off the American mainland, things can get interesting. From what I know (and this could be outdated or wrong, I'm not an expert) the Seminoles had individualist (farmsteads) and also manorial style communities (county size with a few villages). A chief's manorial settlement will attract more commerce from British and Spanish merchants, but the individuals free from the chief will have more opportunity to grow and prosper.
There were also Spanish land grants in the interior, the Spanish will want to settle some of them and lease out other portions to the Seminoles. The Spanish will eventually want the Seminoles to pay taxes so enforcing that will be a problem. When the other Spanish colonies begin to revolt then the Spanish will look to develop the commercial opportunities in Florida.