Not a bad job at all - I rather like your squad. Your week points are QB, RB2 and IDP, but with a trade or two and some wiley pickups you can remedy that pretty easily. Mainly because you're stacked at WR - I love that Green and Floyd are your WR6 and WR7, and I think that you could gain some serious traction in those points of need by dealing Britt (and/or even Marshall) for help where you need it.
You might be a bit behind the 8-ball on quality IDPs as people probably snapped up most of the top 25 overall at this point - in the future I'd say don't wait too long in the interests of snapping up WR/RB depth, as those are valuable starting spots that are hurt by starting WW guys more often than not. That said, you can either pick up a top IDP as part of a trade, make a lesser trade for one and/or try to get lucky on the wire.
I'd rather have Lewis and Miller (in that order) than Keller, and I think that's your first, most logical move. If you have to let three guys go, it's gonna hurt some of that WR upside I was talking about, so I'd try to make some deals before flat out releasing guys. I think Meachem is a clear cut from taht group, and then it's probably Floyd and A.J. in that order after that. Try to find someone who's screwed at WR and offer a deal for an upgrade at RB and an IDP - a deal or two like that and you could upgrade your starters without cutting those WRs and getting nothing for them. If it works, cut your worst remaining guy for a K. If it doesnt, then those last 3 WRs are the way to go IMO ...
Hope this helps