wiring for EFI

Can't answer all your questions.
I have the Fitech. Main power feed is to the Battery, with a fuse. No issues with power drain when motor is shut off for extended periods.
I tried hooking that line up elsewhere at my main power junction box (car is entirely rewired) and found it did not work.
I know for the Fitech that the fuel pump shuts off if there is no rpm signal.
I also use a denso toyota style alternator. Close to 14 volts at idle.

Ken