2) that is entirely NOT true. You should install little snitch and see what happens even if you NEVER sign into icloud. note that the phone home contact is not immediate, it happens in the background at random intervals from random applications.

just some random services blocked by little snitch on a mac:

accountsd, adprivacyd, airportd, AMPLibraryAgent, appstoreagent, apsd, AssetCacheLocatorService.xpc, cloudd, com.apple.geod.xpc, com.apple.Safari.SafeBrowsing.Service, commerce, configd, familycircled, mapspushd, nsurlsessiond, ocspd, rapportd, remindd, Safari, sntp, softwareupdated, Spotlight, sutdentd, syspolicyd, touristd, transparencyd, trustd, X11.bin

(never signed into an apple id)