when you say "loop in" if you mean use something other than the pedal's switch itself to turn it on and off, then no.
if you use the pedal's physical switches to turn on and off, you can go guitar > pedals > axe fx input > amp input & separate amp fx loop signal > cab. this is a bit simplified, but that's the general idea of 4CM.
if you want the pedals racked behind you and use another device to turn them on and off, then yes you need a Pedal Loop Device like the ES8.
there are many ways to set things up.