Are all Spine services accessible through the Spine Internet Gateway?

Sorry to be a pain but looking at the general move towards FHIR/REST etc & away from SOAP etc.

I know Mesh is available (if not quite so capable) on the Inet Gateway vs HSCN/N3 but at the moment…my searching skills are failing me…as I can not find anything definitive on if all Spine services are or will be available from the internet & what if any the differences would be (e.g. like the small message size on mesh of 50MB vs 100MB).

If only some are available… again is there some sort of list somewhere?

Cheers

Adam