Can APK Editor be used to increase the location/GPS Fix Interval? I want increase location fix updates for Google Maps location history (currently 10-15secs) and other location calls on my android Marshmallow device. Can this be achieved by something like APK Editor?
Whether you want to modify the APK depends on your use case. 

You can simply have another app which has a higher location fix frequency, and Google Maps is likely to have fast location updates as the "fastest interval" setting makes it possible to use the faster location requested by other apps.

If you do want to change the behavior of Google Maps, you can go with either Soot (Jimple modification) or ASM (Java byte code modification, which is better for highly obfuscated code like Google Maps). However, this can be a painful task. Thus, I would suggest you go with the previous approach unless you really need to modify Google Maps.