Existence of the word "провинция" is a little bad news. On the other hand the phase out of провинция and introduction of oblast is good news. Seems they had the same purpose / same level. Maybe in more specific articles one would use transliteration.  I agree with your opinion of "Region", for me too it sounds not very administrative. mmmh and county is realy strange. I allways think of US if I hear it. But it is used on SE(sweden)-subdivions and some others. To use county in Europe can cause confusion in some countries because of historic connotations. With content from your table I enriched Subdivisions_of_Russia#Translation maybe you can help with some cirilica (last word was serbo-croatian)