EM1 tracking: FT vs MFT glass.

So even though my GX7 is fairly low mileage, it's also missing a lot of features i would love to use. I knew this going in of course but i just wanted something decent as an entry body. Still, im looking forward to my eventual upgrade and am debating a few bodies.

The GX8 has been on my radar for a while as it's, spiritually, very similar to a GX7 but with new tech goodies. But now the EM1.2 is here and the Mark 1 is much cheaper and it has quite a good feature set. So as it stands, the EM1 will be my next purchase but i was curious as to how and when the PDAF is usable.

I know people use FT lenses with PDAF but am ignorant to the details. I saw 4 FT adapters available, one from Olympus, Panasonic, and 2 3d party options. Are any of them better than the others as far as AF goes? Also, does the EM1 ever use the PDAF pixels when using MFT glass?

Lastly, i hear a lot about how good the EM1 AF tracking was an improvement over past bodies but is that only with the PDAF? How does the CDAF tracking compare to Panny? I have been looking at the FT glass used and there are quite a few i wouldn't mind owning, especially if they offer a distinct advantage with an EM1.

An advantages or disadvantages either way? I thought i remember hearing when using MFT lenses the EM1 will switch between PDAF and CDAF when it sees fit. Is this true, is it a problem for anybody? Just looking for any and all info AF related, feel free to share anything relevant. Thanks in advance.