This is a hypothetical, but depending on the answer, could be helpful down the road. Take a Shure M68 mic mixer, or any mixer for that matter, hook up 3 condenser mics. Take the XLR out from the Shure and go into a USB interface, let's say the Scarlet 2i2, but could be any USB interface. Turn on the 48V phantom power on the interface. Here's the question: Would the 3 mics hooked up to the Shure mixer all receive phantom power? In my limited knowledge it seems as though they should, but perhaps the connections need to be more direct for phantom power.
No. There is no phantom power connection between the mixer output and the microphone inputs. Phantom power must be injected right at the mic input, and there is lots of circuits between the mic inputs and the final output.
Furthermore, applying phantom power to something like a mixer output is NOT recommended because the phantom power could damage the output from the mixer.