Word of advice...
Pick at least one of those alts and play it until you get your legacy. Then all your XP from all your toons will contribute to raising your legacy level. And for every toon with which you complete chapter 2, you will then get that class buff for all toons in your legacy as well.
The game rewards creating alts, but it rewards it more substantially if you level them 1 at a time.
That's why I deleted all of my alts. My Sniper is now 32 and getting smacked around by the final fight in Chapter 1. If I kept my alts, they would all be around 15-20 or so. lol