With the measurement at the fuse box, you need to do things a little differently. While you took out the 4th fuse down, you are measuring on the common feed for fuses 3, 4, and 5. You need to pull all three fuses (circuit isolation). Also make sure the headlight switch is in the OFF position. Also you may want to unplug the inspection lamp under the hood. Also test the fuse box with your doors closed. As @Captain Obvioussaid, you want to make sure you don't have a switch on, and that includes the switches for the dome light.
With the fuses pulled (and the switches off and inspection light disconnected) take measurements to ground at the points indicated by arrows in the photo.
Just for a reference, 2.6 ohms will drain your battery quickly, but it should not burn up your fusible link. That's a little less than 5A draw. That could be a couple of light bulbs you're reading.
As I said in a previous post, reconnect things in the engine bay one at a time and re-measure. If you do have a short, I'm more willing to believe its around the alternator. (When I have problems with my own cars, my first thought is, "What did I f*** with last?")