All good advice from WB and Simon.

And +1 on Simon's comment about the shielding on the pickguard, but nice tidy job on your cavity shielding! Good work!

The only thing I'd add based on what we can see, is re-flow all your solder joints. You don't need to add more solder, just hit them with the tip of a good hot iron just long enough to melt the existing solder.

A cold solder joint can invisible to the naked eye, but can raise hell with the signal path.