Is there a particular time frame in which you're writing? That would affect the answer.

had they seen them before?

European explorers and traders had been to what's-now New England and Maritime Canada long before the pilgrims finally put down roots in 1620. A notable early encounter, in 1535, during his second voyage to Canada, French explorer Jacques Cartier spent time among the St. Lawrence Iroquoians--mainly those in their two major communities--Stadacona (now Quebec City) and Hochelaga (now Montreal). Among Cartier's crew for his second voyage were two Stadaconans who had been taken by Cartier during his first voyage. The two men, Taignoagny and Domagaya, were the sons of Donnacona, the leader of Stadacona. They were taken to France, where they lived for a year before returning to Canada as guides of the second expedition. Once they got home to Stadacona, however, they pretty much left Cartier to his own devices. While Cartier spent a few months wandering around the St. Lawrence River, the two brothers remained in their hometown. As Cartier left Canada, he once again abducted the brothers, this time with their father and seven other Stadaconans--all of whom would die in France.

Hints of European diseases were already appearing about the Canadian villages during Cartier's second voyage. By the time the French came to permanently settle the St. Lawrence Valley, the St. Lawrence Iroquoians had abandoned the region. Two large groups settled north of Lake Ontario, becoming the latter half of the four-nation Wendat Confederacy (or as the French called them, the Hurons). Others might have gone south of Lake Ontario, joining with the Haudenosaunee (the Iroquois proper), particularly being absorbed into the Mohawk (based on the Mohawk-Mi'kmaq conflicts that took place at this time for control of the St. Lawrence). In either case, they would have brought along the information concerning the French that the two Stadaconan brothers had collected--assuming that they had not already been informed by Donnacona before his abduction (Cartier reports that Donnacona was frequently travelling south to discuss matters with his allies and re-appearing in town escorting emissaries from other nations).

From the south, the Haudenosaunee likely knew of the Europeans almost as early. In 1540, the French briefly established a fort at what is now Albany, New York, very close to the main entrance into the Haudenosaunee from the east. If they weren't aware of the fort while it was being constructed, they certainly would have discovered it soon afterwards. There's no direct evidence of Iroquoian contact with the French at this time, however, and flood destroyed the fort not long after it was finished.

Definitive European contact with the Haudenosaunee comes in 1609, when Samuel de Champlain led a failed invasion from the north. That same year, the Dutch laid claim to the Albany area, building a fort there in 1614 (which managed to survive ten years before also being destroyed by a flood) and initiated the fur trade with the Haudenosaunee, undermining the French fur trade with the Wendat.

did word of the ships carrying settlers arrive from tribes in North Carolina after Roanoke?

Several major trade routes and trails ran north-south across the eastern part of the continent, along which people and news could easily travel. While traveling along the more populated trails, travelers could generally count on hospitality of village leaders to find a meal and a place to sleep. In exchange, the travelers often repaid their host's hospitality in information from abroad (and were generally obligated to explain the reasons for their travel, which is why some colonial era diplomats preferred to take more sparsely populated trails to avoid undue scrutiny). Among the trails heading south out of the Haudenosaunee territory were the Catawba Trail and the Tuscarora Trail (not to be confused with the modern Tuscarora Trail that's part of the Appalachian Trail, a recent creation), which connected the Haudenosaunee to their southern enemies and allies, respectively, in the Carolinas. While it's completely possible for a Tuscarora messenger to head north to spread the word about the Roanoke colony, there's not proof that it did happen. And, of course, since Europeans had been showing up periodically from multiple directions in the area for decades, Roanoke would have been just another failed attempt and likely wasn't regarded as anything terribly important to the Haudenosaunee if they had heard about it at all.

My history teacher wants us to write a bio of an archetype of settler in the colonial era and I chose a member of the Iroquois.

I'm assuming you cleared that with your instructor, right? I ask because of the way you worded the prompt as "an archetype of a settler," which puts me in mind of the European colonists and not the indigenous populations they were encountering. I just wanted to be sure you weren't deviating from the assignment too much before you got invested in this idea.