1. To track down the issue you will need to have ampmeter or ampclamp.

If you don't have one, get any that has decent accuracy and will work with DC (as some cheaper ones can measure only AC current).
I bought this one a while back: and its been working fine.

Then you put that around battery cable and look for current. If it's above 0.2A when car was sitting for a while, door closed, no key in the ignition, then you have a parasitic draw.
To find it, pull fuses one by one, until current measured by the clamp drops. If you find that fuse, then you simply go to service manual to find out what is on that circuit.
When you know, you can keep checking other things, mostly by disconnecting them, but finding the fuse is the first step.

2. Did you try taking AC compressor cluch relay out? It's second common draw in our cars.