Hiep, on the decreased DOF, this is well exploited by the m43rds users for years (the is a long running thread on bokeh), despite the very small real estate offered by the m43rds sensor. This is entirely possible because of the sensor stack thickness ~5mm.
I am surprised that no one is giving actual stack measurments after the mod and allude it being same as the M9 and such. They can not be the same as the Sony sensor has an epoxied ~0.5mm clear glass on it. The thin UV/IR cut filter then will have to be 0.4 mm thick. To have that and to maintain infinity focus is not an easy thing to achieve.