Viable, alternative, first round role orders in 5-player Puerto Rico
I doubt there's a significantly different first round order.  Certainly at the beginning there are very few options that are of use.  We often see a prospector in fourth and fifth, the rational being:


If the fourth player produces then the fifth player may take prospector (or trader in the unlikely event they managed to get a small market).
A player on corn wants to save up for a more profitable good.


So in short the five player first round sequences that we tend to see are:

[Settler/Builder], [Builder/Settler], Mayor, [Craftsman/Prospector], [Captain/Craftsman/Prospector/Trader].