Scientists are really powerfull because:
- u get 5 science instead of 3 science from the very beginning in ur capital --> Techs are going way faster than ur competition if u can keep ur city growing early game.
- When u settle and the outpost becomes a city the tech penalty's are reduced if not gone + u get another science boost.
I'm going after these colonists to powerhouse in science .
Refugees look very strong. They can be Engineers if you need them to be. Just work more Mines and less Farms. They can be a poor-man's Aristocrat. If you have Science/Culture terrain they allow you to work it over Farms too.
I'd go with Artists as it looks like most of the science bonuses are actually in virtues instead of science buildings. This also goes well with Franco-Iberia. The health bonus may be more important than food for growth.