@S_bk97 Not sure if I followed the architecture plan, but yes, standard AutoVPN can work in this scenario, meaning that you can have the MX WAN interface of a spoke site connect upstream through the LAN side of another intermediate MX, and have that same spoke MX connect back to a different VPN Concentrator beyond the intermediate MX. However it looks like the plan here is to have that connectivity nested multiple times, so there would be multiple NAT boundaries to consider and there are also sizing issues to consider on the "intermediate" sites. The intermediate MX appliances would accumulate the traffic/throughput from downstream spokes.
I have this running in my own home lab, it's Ethernet based, not MPLS, but I do have a hub & spoke AutoVPN running through an intermediate MX, and that whole thing is all sitting behind my Internet-facing MX. I would suggest trying this in a lab first, or get a few trial units to do a quick proof of concept. Sorry if I misunderstood the plan.