Looking for advice, impending DC and staff move

Hello everyone,

We recently received notice that the company plans to sell the building we've been in for a few years. This building has a data center inside of it that houses are Internet edge, core switching, and server infrastructure and we rent colo space from a provider for DR.

With the move, staff will move into a new building and we will need to find a colo provider for our server infrastructure. There are a lot of moving parts like we just (within past 3 months) added an additional ISP for dual Internet connectivity and bought new ASA 5525Xs for this building and colo. I just migrated to the 5525Xs at this build today as a matter of fact.

Currently, we plan on moving our phone system to the new staff building but eventually might plan to try a cloud-based solution. Also, we do have users who will be using VDI at the staff building provided by servers located at the new DC location. What would you guys be thinking as far as connectivity and equipment from new staff building to DC colo? VPN over DIA? MPLS? SD-WAN? If I go the MPLS route, should I have a DIA as a backup? Do I need to buy more additional equipment like routers or will the 5525Xs suffice?

Thanks in advance for any feedback and let me know if any additional info is needed.