There's a bit of an issue with utilizing the 169.254 tunnels.
Since OpenBSD is policy-based, you'll get a tunnel to the other 169.254 endpoints at AWS. That's it. You can't route traffic through the enc0 interface...so via the first two tunnels you can reach the other BGP endpoints and nothing more.
You *could* layer another tunnel on top (basically, use the same psk and public IPs, but give it the local LAN and remote LAN CIDRs instead of the 169.254 addresses. OpenBGPD can run on the 169.254 addrs, but you won't be able to actually *route* anything, and if your S2S tunnel dies, you have to move it manually, which defeats the purpose of BGP dynamic routing.
See more here:
http://www.linuxquestions.org/questi...bgp-vpn-36539/
Edit - also, if you are going to use gif interfaces for 169.254 addrs, you need to put them in a /30 per the config (255.255.255.252 or 0xfffffffc).