Thanks for your replies, guys.
Now we are trying to implement all recommendations and make it as simple and fast as possible. please share with me any ideas you have.
I agree that GoPro already has mentioned features but it's still 3 apps and videos that you produce with that apps has lack of action. Problems with music, boring templates (there's ~15 templates and songs and if you want more - you'll for sure have problem with music licensing). As for me I usually combine Glitche, iMovie and GoPro studio to have the best results but it's all about time, battery life and software usability.