I recently came back to m43 myself (having bounced around FF and APS-C in the 3 years since I left m43)
I'd strongly suggest an E-M5II over the E-M10's if you can swing it. The used price on an E-M5II is quite affordable and frankly the EVF on the E-M10II and E-M10III is quite poor in comparison. Plus you get more features, a larger battery and better handling.
I personally went with an E-M5II and added an E-M1 to round out my kit a little after. I mostly use the E-M5II, but prefer the E-M1 with bigger/heavier lenses.
I have and love both my E-M10 II and Pen-F. My father has the E-M5 II and my brother in law the E-M1 II. You can't go wrong with any of the modern Olympus cameras, but really have to decide which features make the difference for you.
Weather sealed - 5 II or 1 II
PDAF/CDAF for best action or video AF - 1 only (maybe 5 III)
Custom 1-4 on mode dial (personally love this for quick changes to settings) - Pen-F, E-M1 II (maybe 5 III)
High Res - All but E-M10s
Size of your hands - E-M10 II w/ ECG grip perfect for medium hands, Pen-F with grip too. E-M1 II better for larger hands or larger pro lenses.