Problems with MG2 as plugin in Logic Pro X

I’m trying another new configuration on my 2013 MacBook Pro Mojave. I created an aggregate machine using my iPhone x and my Zoom Tac2r. I’m playing Brian Eno’s app called Bloom which is a generative music app, constantly changing stream of notes of a certain grouping. Sort of like an external random arpeggiator. I have the stereo channel with the Bloom audio set up with no output but with MG2 as a plugin sending on midi channel 2 only and a soft synth on another track listening to that channel. Then I have an audio track for a guitar and a mic also setup with normal Main 1+2 outputs. Then I double those two tracks with no output again but with MG2 in each track broadcasting on midi channel 3 and 4 respectively.
This whole setup has been pretty twitchy but after a couple of hours of work I got it working. But I keep finding weird stuff out about it. For example if I don’t have the other audio inputs being actively monitored, regardless if I’m actually playing guitar, the audio from the iPhone goes to every synth track that is being monitored regardless of the fact that it should not be listening to those other midi channels. No biggie as I don’t foresee that coming up while performing. If I don’t want to hear the guitar I’ll turn it’s track volume down. But it would be nice to understand how this is happening.
Secondly, and much more problematic, this set up is just murdering my cpu. All told right now I’m only using 8 tracks: 2 guitar, 2 mic, 1 iPhone audio (stereo), and 3 synths. I’ve performed with a lot more than that and had a very quiet system but this is crackle overload city. I’d really like to have more tracks available.
I should add that I double the guitar and mic tracks because I found that as soon as I put the MG2 plugin on a track, normal output is shut off. Any insight as to why this should be such a heavy load on my CPU? Granted I only have 8 GB of memory on board but that has taught my how to be frugal with resources. I’m hoping to perform with this setup in a couple of months but thinking it’s about time to buy into the new 16" MacBook Pro’s despite the known current limitations like no MidiBass and no driver for my Motu unit yet. But the Zoom and MG2 are supported so I could hopefully get this concept up and running and stress tested before my gigs.

You can open the MG plugin, and choose “DIRECT” in the 2nd fx slot in the guitarchannel. This will forward the dry signal through the system.

"…regardless of the fact that it should not be listening to those other midi channels. "

MIdi channels in Logic behave strangely, not logically.
In project setttings, tab Recording
“Auto demix by channel if multitrack recording” must be enabled if you want to adress different synth via different midi channels with different controllers.
For more info about how midichannels can be used in Logic, see https://macprovideo.com/article/audio-software/logic-pro-x-a-guide-to-multitrack-midi-recording

Whoa, “Direct”?! I had no idea. That is brilliant. Is there a new manual that describes some of the effects you’ve put into MG2? I am absolutely guilty of not looking into very much of that at all. Unfortunately that didn’t improve over all performance . The CPU is still wacked. Crazy thing is if I open the MG2 plugin window the load noticeably decreases, until I play some notes. That doesn’t make sense to me. It’s not like opening the plugin window takes the plugin off line. I can still play. How can that possibly decrease the load? Though if I don’t touch anything for a while the CPU meter goes down to very little load, as I would expect to look like. But even then if I play one note it’s crackling like crazy. That and every time I close Logic and reopen the midi channel for the tracks plugin changes, always back to 2 instead of 4 or 5.

I did know about the demix setting, thank you Paul, from a previous conversation with you. Every thing is so unstable it’s like playing whack a mole. I’m wondering if Apple hasn’t rendered Logic unusable for Mojave. But I’ve never tried this configuration before so I have no previous experience to compare.

It may be Mojave. That system is a beast! I use Mojave for mixing only on a 2015 Mac Pro. For inputs and recording I use High Sierra on a 2009 Mac Pro. I can load that thing up and have no problems. You might try High Sierra on another partition.