Yolanda,
Do you have your g grandfather's Qld death certificate? This should (may) give his parent's names.
If he had any children born in Qld have you checked their birth certificates to see what the surname is written as. The name will have been anglicized so it will be difficult to "convert" back to a Russian surname. On arrival it's likely that he just said his name and it was written as it sounded. Did he call himself Sologinkin after he'd been in Qld for a while? I have a good Russian surname list however the link appears to be broken at the moment. I will check again later. A google search reveals loads of Sologinkins - are they all yours?
I believe that even if you do speak Russian, research there, specially from Australia is difficult if not impossible. There are people who will do this for you for a price. Not sure I'd trust them myself.

Apparently it can help if your ancestor was a member of an association or had a profession which may have kept records, a member of royalty.

The good news is that there IS a place called Aganty in Russia which I'm sure you've located on a map - fabulously isolated!

I'm not sure if it will help but next time I'm at the Qld State Archives, I can try to find some more information about their arrival in Qld. A more detailed passenger list perhaps?

It might be worth asking older family members if they know of any family stories which might help trace the family.
I'm afraid that you might be fighting a losing battle though ....
