Will the Secret Space Program mercenaries be the “boots on the ground” for the planned annihilation of humanity, while the technology used to locate, round up and root out people will be predominantly manufactured by and utilized by the Greys who expect to do what’s needed from the safety of cloaked ships?

This is a correct scenario in some respects. The plan is to use the Secret Space Program mercenaries as the point of the spear in directing killing energy at clusters of human population, and so they will be directed at many population centers. The mopping up operation to carry things to the final conclusion will be done by an army of human clones. It is these that are being contributed by the Arcturian Greys, and they will be deployed accordingly by the Greys into the field to carry out their duties and mission to finalize human destruction. As a separate activity, they will be acquiring and sequestering those humans of personal interest to them for their hybrid optimization program and those humans will be moved into underground shelters for the time being, and essentially enslaved to serve out this function, to be, in effect, laboratory animals for their genetics program.