Two of the routers , the Netgear 6300 and the Asus RT-AC66U are the new Ac band routers and while they are G/N compatable to take advantage of the Ac band it will require new adapters fot any computers that you want to have use the Ac band.
There's nothing wrong with getting these routers I just wanted to let you know in case you weren't aware of it.
That being said the Netgear 6200 would also be a good choice to add to your list.
The router that I might go with would be the Asus RT-AC66U and the reason for that is the antenna's are on the outside of the unit and you would have the option of changing to a bigger antenna to give more coverage area and a stronger signal.
The Netgear 6200 would be the next choice because of the three Ac band routers that we're discussing it has the better feedback and is one more usb port and some additional bandwidth worth $35 more ? That would be your decision to make.
The other N routers are now yesterdays technology and with building a new network with new equipment it's also your decision if you want to have some future proofing and have the flexability to have the Ac band available.
Of the N routers on your list the Linksys EA4500 would be my choice , I have the E4200 and it's very easy to use and set up and has a good amount of features.