OMD: Can I take the same pictures with the 12mm f2.0 and the 17mm f1.8 ?

The 12mm is too wide for portraits.  Your subjects won't like the distortion, and you'll get a bunch of extraneous peripheral detail in your shots.

17mm is equivalent to a 35mm FF lens, which has been used by photographers for decades as a "standard" walkaround length.  It's still a bit wide for portraits, but much better than the 12mm.

Consider the PL 25mm instead.  It will give you great portraits, but will still be wide enough to take environmental shots if you choose.