Advice needed on BoinxTV + multiple cameras setup

Hi there.

I need to bring in streams from up to 3 cameras at once into my MacBook Pro (15", early 2011), possibly swapping out one camera for input from an iOS device. It looks like BoinxTV will handle things just fine on the software end, but my concern is with the hardware.

Given I have only one FireWire port and it’s a FW800, here’s the setup I’m considering.

Source 1:
Canon M400 + HDMI to FW400 cable + FW400 to FW800 cable

Source 2:
Canon M400 + component to VGA cable + VGA2USB adapter + USB cable

Source 3
Canon M400 + component to VGA cable + VGA2USB adapter + USB cable -OR-
iPhone 4 + Apple dock to VGA cable + VGA2USB adapter + USB cable

Will this be a decent setup for these sources? My concerns are the input frame rates from the sources, honestly. I’m all right with SD given my constraints.