You have done so much that you are totally lost and confused.
You are now grasping at straws and are starting to easter egg ie throw parts and money at the problem
1. PROBLEM STATEMENT
Battery discharges overnite
Possible problem bad battery (shorted cell) Or you have something in circuitry draining battery,
SOLUTION
replace battery with one you KNOW is good ie from another vehicle. Charge the bad one and check gravities if you can.
IF that does not help then install an ammeter or lite bulb in series with battery. IF lite lites and KEY OFF then you ahve something draining battery
start by pulling fuses ONE at a time and checking lite. When it goes off you know your problem circuit. Now check each load on circuit.
Dan Bentler
