I suggest to transfer surviving soldiers from the Prologue (training mission) to the main game to get more immersion and player involvement in the game's plot (as done in XCom1 and 2; or Phoenix Point).
Heck I love to give it a shot and help you out! With the addition of the modding tool I feel like we can help you out with your roadmap, especially when it comes to making new maps, which is a huge factor in these kinds of games.