Hello Paulo,
the scenario is rather complex for the presence of the backup DMVPN.
If that wasn't present the approach would be:
CE routers facing MPLS provider PE routers will be running both OSPF and BGP.
You run eBGP sessions with PE routers.
From the eBGP session routes about all other sites are learned and can be redistributed into OSPF.
Inside the BGP process network commands representing the local site and lea via OSPF can be used to advertise in BGP local networks.
Doing so all other sites ip subnets will be some form of O E1 or O E2.
So on the central site if the DMVPN headends are different from the MPLS CE devices you need to use a trick:
you need to use two different OSPF processes on the DMVPN headends to make backup routes of the same type O E1 or O E2 with greater metric otherwise DMVPN OSPF routes if not external would be preferred
On remote sites if multiple routers are present you need to use the same trick if the CE router and the DMVPN are on the same router the less AD of EBGP in comparison with OSPF should work.
Edit:
on remote sites connected to both providers to reach HQ and DR you need to provide preference to HQ primary link
you can use
neigh SP1_to_HQ.ipaddr weight 500
to prefer to route to HQ
I'm not sure if something has to be done for the return path, being two different service providers should be enough to prefer SP1 everywhere including HQ and DR sites
Hope to help
Giuseppe
