Mesh portals and points are still campus APs. Portals have a wired connection to the infrastructure and Points are expect to connect back via a wireless uplink.
I reread your post...is there a technological challenge or user experience issue that needs to be solved?
If you are just plugging in an CAP that is outside, you only need to provision it as mesh if (1) It is providing mesh services to another AP, or (2) it needs to connect to another AP as mesh. Otherwise, it just needs to be a Campus AP.