Three Person Team Best Practices?

I've been solo coding (with a bunch of minor contributor/collaborators) a project for a while. We're adding two junior developers to the effort, both who have cut their teeth in enterprise/startup type environments for the last 5 years or so. One of the things that appealed to both of them, was being part of a smaller, less constrained/bureaucratic effort. And or me, I've hit that point of "go alone go fast, go together go far", so I'm excited too. I've been part of different teams in the past, and was a big advocate of XP back in the early days of Agile movements.

Somewhere between my disciplined cowboy crusade, and the ticket driven cube farm experience these guys have had, is a happy medium, more regulate than what I've been doing, and much less regulated than what they've been experiencing. I'm curious any feedback/suggestions from others in a 2-4 person team of best developer practices. I will prefer discipline over process, but recognize there has to be some process. We use git of course, and currently are (mostly) focused on mobile dev efforts (no web things).