M13 4 cable method - does FX loop on amp HAVE to be on?

[tdopz]

Sorry if this is a dumb question, but interestingly enough after spending hours and hours playing with my pedal board configuration, I came up with the 4 cable method(I bought the m13 used, no manual). It wasn't until I did some googling that I found out it's already a thing and there's some good info out there. I also discovered through googling that I was running everything in front of my amp(pre>all). I never noticed this, because I have 2 settings stored on my amp's midi floorboard(more like 16, but for the sake of simplicity, lets say 2): One with FX loop on, one with FX loop off and with it off I didn't get any FX(pre-all setting sends all effects through the front from what I've read). My FX loop off gets seemingly normal, dry sound, and when I turn the FX loop on, all of my effects turn on. I assume because it needs the FX loops on in order to complete the chain. So while none of the FX on my pedal are going through the AMP's FX loop, it still needs to be on to hear the FX. I also tend to get some weird noise sometimes when playing without my FX loop on(high gain channel), like a quick screech after I stop playing/mute the strings. I'm guessing this is related as I don't get any noise playing directly to amp. 

So, do I have to have my FX loop on all the time in order to use the 4 cable method? Is this what is causing the noise? Some strange incomplete chain thing? It's important for me to be able to set up what fx I want to have on before I get to the part and then press one button and have all FX on at once(I have more pedals than just the m13, or I'd just use the scene select mode). Is there a work around for this or should I just run the whole thing through my FX loop like a normal pedal chain(which would prevent me from running compressors and the like before the preamp)?

Amp: Engl SE-670
Current chain: Guitar > Boss FB-2 > M13 in
M13 fx return > AMP FX send
M13 FX send > digitech whammy > AMP Input
M13 out > Big Sky reverb > AMP Return.

[toonsms]

Yes I believe you do.

 

Something else I have noticed that if you have the M13 off the signal to the front of amp is not there. The signal to the return is.