Grigorij probably for Latvia. This time our Saeima (parliament) decides about getting citizenship for him, but this not yet decided. So probability is 50/50.
May be main reason for joining Latvia is fact, that for 3 Years (2004-2006) due to bureaucratic reasons he have not ability to ride in all official rides inside Russia (very complecated story - some people think that Grigorij wasn't right some people that Federation. So similar to Ferjan and Slovenia). Though he was 20-22 Years old for that time he rides only few (2 or 3) times for these 3 Years in individual meetings in home town - Vladivostok. And if I remember correctly in all these meetings he was in top 3. However, for that time some people thought that this conflict is never ending and he would finish carrier.
Fortunately, he joined Daugavpils team in Polish League 2 in 2006 and became a leader of the team (Y-2006) and after that - TOP rider for whole league.
So he is big talent and only 23 Years old. Let see what happens with him next Year in Polish League 1.
Artiom - definitely would ride for Russia. I have not heard information that he want to change citizenship.