I'd take Len's overall potential before any of those players but I can easily see an argument for Adams and Gobert and maybe even Olynyk. But why on earth Noel? What has he done that has you putting him above Len?
Every player you listed has logged more minutes than Len so they've had a better chance to put up numbers but none of them are exactly killing it out there. The more they play the more apparent their limits are but the opposite has seemed true for Len. He's the 2nd youngest of that group (Noel is 10 months younger) and has played the fewest minutes. He also came to the game much later than your typical big man.
They have played more minutes because they are probably better.
I'm not a huge fan of Noel however I do think he has more value than Len at this point. The biggest issue with Len is his ability to stay on the court. That means health wise and also foul wise. He averages 5 fouls per 36 minutes. For comparison, Noel averages 3 fouls per 36. Also, I admit I haven't watched as many 76er games as I have Suns games but from the Philly games that I have watched, Noel seems to have better hands and catching ability than Len who has a really hard time catching many relatively easy passes.
I know Len realized that he has horrible hands too and said he bought a football machine to help him with it but I'm not sure its improved all that much. Hard to get a "stat" on this because often times stat keepers give the person who passed the ball the turnover if the recipient (especially in the post for a big man) bobbles it or drops it.
I have held out hope for Len for this long but I figured by his 3rd season that he'll start showing something but I'm not seeing much. I admit perhaps I had higher expectations for him because he was our highest draft selection since Gilliam. However, I think his ceiling may be Robin Lopez while I would rather not even think about what his floor is.