1. I would assume that a Proprietary Government would be installed in your Colony in the start. Depending on whether or not this is a real Colony or a random, fake colony, I would say that people would populate your Colony on grounds of location, gold, or community attitude towards specifics.

For example: Is your Colony Royalist or Parliamentarian? Do they like Catholics or are they Puritans? Is your Colony based around finding gold, like Virginia, or are they seeking rich land with which to become rich with?

Strategic location, again, depends on if this is a real Colony, like Jamaica, or a fake one. If a fake one is your choice, than I can't really say, but if it is real then maybe I can provide some insight. Georgia, established 1735, was designed to be a buffer-state to protect South Carolina from Spanish Florida.

2. Tobacco was rich in Virginia, tar in North Carolina, I imagine your export would be sugar made on sugar plantations. Indentured servants, white slaves essentially, could be used in the beginning, depending on Proprietors wealth, but Africans, once it was discovered that they were fitted well for America's Caribbean climate, would replace Indentured servants quickly. I would say, depending on location, that a trade ship could show up within a day, days, a week, weeks, or months if coming from England. Dutch, English, both countries would trade in your sugar exports and give you whatever they were selling. Slaves, tobacco, etc. Your Colony, concerning self sufficiency, depends on internal and external factors. How bad is the Pirate problem? Is your Governor Catholic and the rest are Puritan? Your Colony's survival depends on whether you can show your start-up settlement as a rich undertaking to other powers, like a business pitch, and combat diseases that could be brought upon your settlers.

3. Depends. If a Spanish fleet blockades your port before you can send a message, which can be only by ship, then your screwed if you don't have the cannons or Hurricane Season doesn't work in your favor. Let's say a storm brews off the coast of your Colony during this blockade, that could send the Spanish packing.

During the Pirate blockade of Charles Town, Blackbeard, with one more, or more, ships, blockaded the harbor, taking town officials hostage. Can't remember how he had taken them, but nonetheless, he took them and ransomed them off for medicine for his crew, considering they had sex-related diseases.

People would come to your Colony and stay based on your sale's pitch of how good the Colony can be. Others may come when a permanent settlement, like Charles Town or New York, becomes developed to the point of being civilized and the modern features of your Colony could exploded its coin purse with so much money.

If your settlement is poor, the people are poor, the shape of the port is poor, then your Colony could fail totally and collapse.

My two-cent in on your question. Hopefully I answered them to your liking.

Cheers!