Some of us are talking about live use here and some are referring to in a studio environment.... Which doesn't aid a constructive discussion if you aren't specifying which... You're just putting in your 2cents, which is fine and all but furthermore without really considering the original question.
On that note; for many, using the Kemper is about down-sizing (and as such, carrying extra to a gig for example is unnecessary when the Kemper main outs can deliver these 'entire rig' profiles anyway ie. Guitar all the way through to mic...including mic choice/preference/flavour and placement - this is what the profile details in fact...) which is why I asked what is aiming to be achieved by blending the 2? In a DAW environment as suggested you can just delay a track or nudge it... But I'm guessing this is referring to live / latency-free scenarios how to avoid phase problems.
EDIT: moreover, my understanding is if you wish to use guitar cabinetry (through the Speaker Out of powered Kempers) you engage "monitor cab off" NOT turn the cab emulation of using the soft button from the Amp/EQ/Cab 'stack section' - as this would disengage the cab emulation for the Main Outs (ie. That you would want sent to FOH for PA systems that are FRFR)