SVIs and vPC

I have a pair of Nexus 3500s that have a number of SVIs. Northbound, everything goes to a single switch. Right now the Nexus switches connect to the upstream switch via a number of separate links. I want to consolidate these separate links into LAGs from each Nexus into the switch. I don't have any experience with Nexus or vPC, but from what I've read so far, I think my design is going to run into problems. I'm mostly writing this to check my understanding on how vPC works, although I'll be the first to admit that I am doing this half-blind without really digging deep into the docs, and that is not the best idea.

To summarize the basics of the existing design, I have 3 VLANS. VLAN 123 is a big broadcast domain that both the Nexus switches and a few upstream routers connect to and peer via EIGRP. Each Nexus has another SVI that exists only in that switch that are eBGP peers with an upstream provider router (for redundancy if one Nexus fails)

I really want to consolidate these links, but I see two problems with how this would work.

If I don't use vPC, and ran VLAN 123 across a separate link between the two Nexus switches, I would have to rely on spanning tree to prevent the loop that the two Nexus and one upstream switch would cause, but I would really rather not run spanning tree and I don't want to create another connection between the two Nexus, as there is already the existing vPC peer-link.

If I go with vPC, I have an issue where the two BGP VLANs won't work as traffic could go to the "wrong" Nexus over the member-links. I think the solution here is that I have to run the two BGP VLANs across the vPC peer-link, even though I would prefer to not have them span across both Nexus switches when they only terminate on one. Also, I think EIGRP will break (or take the suboptimal path through the upstream switch because of the forwarding rules for vPC.

I inherited this and I'm somewhat limited in how much I can change the L3 design.

Here is a drawing of what I want the physical links and SVIs to look like: http://ift.tt/2En5LR7

Something tells me I'm missing something or going about this completely wrong. Any advice?