http://forum.mikrotik.com/t/2-wan-2-lan/104149/1
http://forum.mikrotik.com/t/routing-2-wans-and-2-lans/109661/1
http://forum.mikrotik.com/t/dual-wan-in-dual-lan-out/101632/1
http://forum.mikrotik.com/t/dual-wan-dual-lan-setup/118588/1
And others.
A1. Yes.
A2. Yes. And by winbox too.
A3. All of them. Just take care about the cpu performance, it is not clear what throughput under what conditions do you expect. I would choose hap ac2 from your list. Compare the performance and block diagrams.