So my question here is, is there a setting on the a6000 where, with the flash popped up, it is possible to turn the flash off AND adjust WB to a custom setting? I find that only one or the other is possible but I hope I've missed a way to do it.
You can take a pair of magnets (strong neodymium ones) and put them on the back of the housing, near the pop-up flash, one inside, one outside, so that you can use the outer magnet as a handle to move the inner one. The pop-up flash has a small magnet inside, and the camera has a Hall effect sensor to detect when the flash is down, so if you put a strong magnet near the flash housing, it will trip the sensor and the camera will behave as if the flash got pushed down.