Just unhook the plug going to it. If you are really paranoid about it somehow shorting, wrap some black tape around the plug. The ECU has nothing to do with that particular light either.
That rubber boot over your distributor...I wouldn't remove it, it doesn't weigh anything and it's an insulator against moisture inside you distributor cap, living here in the north east, with crazy weather, it would be a gamble I won't take. My two cents
With removing the insulation on the hood dont you take a chance at toasting the paint on the hood directly above the carb/TB? I know my paint there is looking lighter. And I still have the sheet in.
Joe E.