You mention the Apple references but it seems like you might not even be designing for iOS, or at least are looking more for UX advice in general than for the preferred choice on iOS apps.
Using my pretty new Android phone, if I open my text messages and hold-press on an item it selects it and shows a checked circle on the left just like in your Apple images.
I've deleted messages using this before, and as a user perspective I didn't find it confusing because I had first long-pressed on a row, and then the circles appeared with the 1 from the row I selected highlighted. I triggered it so it was obvious what it meant.
If I navigated to a new page and there were circles all down the side from the start I might think it was a radio list, but because they appear as a result of my action it seems obvious that I can choose multiple.
Anyway I think this is not only used by Apple, so if you are looking for some reference to show that Apple only uses them in certain circumstances, well Android uses them too so it seems more universal than that.
My understanding of Apple's design philosophy is to design products that can be easily used by idiots (because if idiots can use them, smart people can too, so it means everyone can use them). Contrast this with Microsoft's design philosophy of designing for middle-of-the-range people which can be difficult for idiots to use, and the Linux design philosophy where you require a PhD to connect to the WiFi.
Smart people can use layouts designed for idiots too, so it makes sense to do it this way.
Anyway for this I think it won't be confused as a radio list if the user's action triggers the circles to appear.