I don't know about Hill's "one or two years" statement. Wallach was saying the other day on Twitter that even if en banc review is granted, it's not crazy for it to be reheard and decided by September.
If there's a big delay in ultimate resolution of the case, I think that a big delay will only happen if SCOTUS agrees to hear the case.
If the en banc review happens and a decision issues by September, say, and the loser asks SCOTUS to hear the case, SCOTUS would probably make its decision whether or not to hear the case by November (I'm basing that on a SCOTUS media guide that says they average taking 6 weeks to make the hear/not hear decision). If SCOTUS denies, that's the end of the line. So it could be all over by this November.
(Actually, if CA2 denies en banc and SCOTUS denies certioarari, it could all be over by the first Monday this October (SCOTUS doesn't act on post-June petitions except in emergencies (think death penalty stuff)) but lets them pile up over the summer and releases lots of the hear/no hear decisions on the first day of the new term.)
If SCOTUS does decide to hear it, then it depends on when SCOTUS makes the hear/no hear decision.
Now, if they do decide to hear it then Brady will almost certainly play the 2016-17 season w/o a suspension because there's no way they hear and decide it before the beginning of February given the assumed timeline. If they decide before the 3rd week of January to hear it, it will likely be heard in the 2016-17 SCOTUS term (Oct-June) and decided by the end of June 2017. If they decide after the 3rd week of January to year it, then according to the SCOTUS media guide it won't be heard until the 2017-18 term. But since it would be one of the first cases added for that term, it would probably be argued in Oct or Nov 2017 and perhaps decided before the end of 2017.
Putting that all together, I'd guess the possible timing outcomes are:
* All over by this Oct/Nov (ultimate loser before CA2 petition SCOTUS, SCOTUS denies)
* All over by Spring 2017 (ultimate loser before CA2 petitions SCOTUS, SCOTUS accepts in a typical timeframe)
* All over by Dec 2017/Jan 2018 (ultimate loser before CA2 petitions SCOTUS, SCOTUS accepts in an abnormally long timeframe).
Actually, I suppose I'm too hasty with "all over", now that I think about it.
First, if en banc review is granted it is entirely possible that the en banc court decides to only throw out what Berman decided but remands to him to decide the other things. The NFL could ask SCOTUS to hear that. Say SCOTUS denies it in October. So now it's in front of Berman. Then when he's done with that go-round, the losing side could appeal that to CA2 and then the loser there could try for en banc and then petition SCOTUS.
Or here's one (highly unlikely!) that could take even longer. En banc vacates Berman but remands for consideration on other things. NFL petitions SCOTUS to hear that appeal. SCOTUS a very long time to decide but ultimately agrees to take the case and in Dec 2017 upholds CA2. So now it goes to Berman. Then the loser there appeals to CA2. That could take you all the way to the end of 2018.
TL;DR: If SCOTUS won't take the case it'll likely be all over by November at the latest. If they do take it, then tack on another 5-6 months at a minimum.