I have been asked to take some casual family portraits for family. I'd like to take them outdoors to give a nice natural fell to everything.

I've never thought about taking portrait photos before so I don't have much necessary equipment. So I was thinking of getting the:

AF-S NIkon 50mm 1.8
SB-600 Speedlite

Are these two things are both good for portraiture and anything else that I might photograph in the future?

Also, any outdoor family portrait tips for a beginner?