Multiple BGP Sessions Possible?

We have two Layer 2 Megaport connection to AWS.  We'll be using eBGP with a private AS for advertising routes.  We'll also be using ECMP.

We just had a vendor ask us to setup 4 IPSec tunnels and use eBGP to route between them and us.  Not sure yet if they want ECMP or not.

I'm trying to wrap my head around the best way to do this.  We're using a single VDOM and am trying to avoid multiple VDOMs.

I plan on using distribution lists to control what gets advertised to each neighbor.

Questions:

1. Can I just set all of them up as neighbors under the same AS?

2. Will having "set ebgp-multipath enable" cause issues or have unexpected results?

3. Would "set local-as" help?  I read the documentation on this and I don't quite understand the purpose of it.

Any help in designing this architecture would help.

Thanks alot!

Matt