It'll depend on the schedule of Runtime, and the Esri projection engine. New coordinate systems and transformations are added to the projection engine first (pe.dll or jpe_sdk.jar), then other Esri software packages incorporate the new library.
For instance, if someone got me the definitions within the next few weeks, I could probably get the them into ArcGIS 10.5 (Desktop/Server), otherwise, depending on when they're available next year, possibly ArcGIS 10.5.1. Runtime's schedule is a little different. We have think about whether we let an SDK that's can be used to build client software have definitions that aren't yet available in the Server software.
To request additions, contact technical support, or me (mkennedy at esri), but it's a lot easier to track if it goes through technical support. In parallel, or I can forward the information, submit to the IOGP's geodesy subcommittee which maintains the EPSG Geodetic Parameter Registry.
Projected CRS names
projection and parameter values
unit (meters and feet?)
Geographic CRS
exents, both rectangular and polygon
Agency Source
Melita