I'm starting a group for game development. I was wondering what type of skills I would need for this to happen?

Answer 1

Designer
Artist
Programmer

Mainly these three. Music and stuff sometimes can be gotten from third party source. But you can git a musician and moar people.

Now if you wanna be an indie, you going to learn how to draw, design and program a game.
Programming language? Depends on the engine. You can also create an engine yourself.

Answer 2

Depends on what kind of game it is and what is a target platform.
Is the target platform mobile devices? If so try to learn C# and Unity game engine. IMO it's a good start.
Does it need AI? Probably here you will need to get some knowledge of State Machines, algorithms for finding the shortest path.
Will it have network communications? Does it require a complex web server? You can write your own or use existing generic one.
Also it will be plus to know how to pack textures, how to write shaders. Understanding of OOP is a must have.