Hi Elena - sorry I haven't been around (very busy

)
Looking at your pics, it looks like you're using your umber like watercolour? I'd guess it's far too dilute with solvent (though I might be wrong, it can be hard to tell from a photo).
I'll talk about trying to do a reasonably "straight" copy _ I've got no objection in principle to doing the "picasso-esque" one (its a fun idea), but all the core technical oil-painting ideas are better demonstrated, I think, on the straight copy.
I tend to think of
lines as only being for initial placement - for example, at the edge of the face against the dark background - one might initially put a line there, but really, its not a
line, but an edge between an area which is light, and an area which is dark.
My approach here would be to spend around maybe 30-60 mins just putting in rough edges as thin lines (I find it useful initially to mark lines as straight line-segments - try to think of edges as runs of "straight-line followed by bend", rather than as continuous arcing curves - it makes identifying changes of direction and inflections, easier.
In the same session, while my paint's still wet (so it can be easily removed, or adjusted), I'd then modify this, blocking-in areas of light and dark, and trying to get initial shapes of areas roughly correct. one needs to identify those edges which are sharp, from those which transition more softly.
Its also important to essentially paint what you can actually
see, rather than what you
think ought to be there - for example, in your various copies, you've painted the ear quite light and readily seen, whereas in the original, its so much in shadow that its scarcely visible.

Its important to try to get the
values right, work out how light or dark different areas of the image are.
Look at this greyscale version, for example:

We can see where areas are, between black, and white.
As a painter, we generally start, at least, by simplifying (detail mostly comes at the end of the painting process).
One way of simplifying is to squint, to try to blur out detail, try to look at the scene as large masses:

Another thing we can do is to arbitrarily try to assess the scene in terms of stepped values:

Note that the picture here is simply irregularly shaped patches (though the hard edges to the patches are arbitrary, determined here by whether they fall above or below certain thresholds. This might seem a rather mechanical way of thinking about things.) But we're not thinking about things in terms of "features" but only of abstract shapes. Get the abstract shapes right, and the "features" draw themselves!
A more "painterly" way is to go back to our slightly blurred version, and look at the
planes that make up the face (and scene). What I mean here by "planes" is the idea that the surface can be approximated by a series of flat surfaces turned at different angles to the light. If we can try to identify these
planes, and where the
plane-breaks occur, and how they vary in value, this can help us depict the form.

I'd like to strongly emphasise that, while I'm demonstrating these ideas using photoshop here, I'm
not necessarily advocating this sort of "high-tech dissection" of the image by computer - but rather, I'm pointing out the sort of conceptual processes that realist painters do
in their head, when looking at a scene.
I'll follow up with an actual demo of first stages, if you give me some time to get it together across the weekend.
Dave