After reading through a lot of different good and not so good ideas posted here (including mine) about a season without Jordy, specifically bringing back Jones, IMO it will be better to stick with what we've got. I don't think Janis is a starter yet, but he's the closest thing we've got - in terms of height and speed - to play outside. There are two preseason games left so let Janis start with Rodgers and the first team. Get the guy some reps real time and let him work on 1) chemistry with Rodgers, 2) route running, and 3) catching. Although I don't think he has that much work to do on catching. Yes Jones knows the offense but he's older, and never played as fast as Nelson anyway. And please stop giving Janis punt return reps. That's gonna be Hyde and maybe Montgomery anyway.
As for White, I just don't see it I guess. Maybe I'm missing something but I have a hard time seeing him on the 53. Then again, if someone else on the depth chart can't outplay him in pre-season, White will be on the roster almost by default as the #5 - assuming the 1 to 4 order is Cobb, Adams, Montgomery, Janis.
And Cobb on the outside doesn't add up. First of all he's much more effective from the slot or even the backfield. And second, he doesn't have the height for outside receiver in today's game. Well, at least not enough height to play him there consistently. Although he could be very dangerous on end around plays. I don't expect Janis to be the next coming of Jordy, but give him a real chance now, before the games count.