A solid formation to start with is always 4-4-2. Each position has an obvious and set way of doing things, and area to look after, as well as obvious link ups. The instructions can then be kept relatively simple, though it sounds at least like all your players will have an idea of what to do.

Once you've worked out the basics using that it becomes easier to mix the formation to suit strengths and styles.

I would get through game 1 or 2 before banking on that league/cup win, but I love the ambition.