Hi:
While far from an expert in Slovenian names, I would expect
Vrabecz is probably Czech in origin. The Vrabec variant may
be Slovenian - I'm uncertain). My grandparents had a farm in
central Wisconsin and nearly all of their neighbors were
immigrants from Slovenia - names like Zallar, Zevnik, Pakiz, etc.
You may wish to look at
http://feefhs.org/slovenia/frg-sgsi.html.
One of the things you'll find is a list of names. I hope this is
of some help!