Rolling for stats is great fun!
You know what's even
more fun?
At session zero, everyone rolls their stats together as a group, and can communicate with each other about who wants to create what (partly based on the scores they've just rolled) and can work together to be part of each other's backstories.
One side benefit? You are overseeing the whole operation, and you'd catch anyone who would be foolish enough to cheat right in front of you.
The players can have no valid complaints about this (Awww, I can't cheat if you're watching me!), except one: "it takes me a week to think of a coherent and interesting character". Fair enough. I'm like that myself.
Solution? After session zero, the players can go away for a week and complete the design process, bearing in mind all that has been discussed and that you
wrote their rolled stats down (for administration purposes, of course!). Next session, after you peruse their sheets and the players introduce their completed PCs to one another, you can begin the adventure.