Connecting 'vacuum amplifier' causes hesitation off idle

I would run the vacuum advance directly from the sparkport. If there is no spark port, I would make one.This is the most important.
The charcoal canister serves a very useful purpose.I would keep it.
Obviously the PCV has to stay.
The EGR system, can be ditched, but when working correctly, serves a very useful purpose. I would try to keep it. It must be disabled at idle and on a cold engine, and at WOT. It must only work at part throttle; And with the amp on there, EGR is varied proportionly, by the venturi vacuum; very nice.
I would verify that all of the diaphragms, and switches,are working correctly and that every thing is correctly plumbed; and then I would leave it all in there. There is nothing in those systems,that if working correctly, makes trouble. If you ditch any of it,except the EGR, you may have other issues. In rare instanced,disabling the EGR can cause problems.