Though I'm still young (well pretty young at least, reaching in on 30). I have written some in order to get DOS to do things for me. However, I can't really say I have utilized them in the last 10 years or so. Nowadays I usually create some command prompt-exe or some graphical windows forms/WPF-tool. This since it makes it easier to improve and extend into something useful that other people can use. What do you use .bat-files for and why do that instead of a program?

I'm not sure you really should subdivide it into roles other than "let one guy make the calls in collaboration with the others". In game development this is commonly referred to as "lead programmer". Give this person responsibility to set up a time plan, discuss it with other people (designers, graphic artists, project leader ...) Once you have a timeplan you see what needs to be done, then just make sure that every programmer on the team has something to do every day and be sure to divide the tasks between you. Making sure that everyone gets something fun to do during the timespan that they can look forward to.