Well, I think I discovered an even better solution for all this, and I updated the OP to refer to this post accordingly.
- Turn on Reduced Latency When Monitoring.
- Do not place any latency inducing devices in any signal path through which you are monitoring machines you are syncing or instruments you are playing or triggering with a hardware sequencer, EXCEPT for External Instrument device.
- The External Instrument device does not seem to add latency to the INSTRUMENT tracks on which they are placed.
- Latency inducing devices are completely fine in any other signal path, including monitoring already recorded audio.
I had long ignored the Reduced Latency When Monitoring setting, because I thought it caused other problems, but it does not.
Reduced Latency When Monitoring basically means Ableton is recording what is “played” vs what is “heard.” So, e.g., if you are playing a guitar through a plugin, it will record what you play, before the latency, instead of what you hear after the plugin (which is the default). I do wish they allowed that setting on a track-by-track basis.
And, if you are monitoring a drum machine, it will make sure you hear it and record it before the latency.