Thanks, Joanna and Antonio!
Although I have to say that having an apartment on Millionnaya (actually, I have two
means a lot of headache, first of all. They are in such a bad condition after more than 80 years of hell, that one really has to restore them. I receive some preliminary calculations today and, for example, the restoration of the beautiful ceilings in one of the apartments would take more than 1 year. Anyway, they are worth it (as does the view from the balcony to the two palaces
As concerns Nikolai Sablin – I could not find any info on him. I have some info on the ownership titles on Millionnaya, but could not find him on the list. Probably, he was renting an apartment: at the end of XIXth century there was a few apartment houses for rent. After the revolution he immigrated to France and died there in 1937, as far as I know. I do not think I can find any information here in Russia on this period of his life.
I’ve found a couple of pictures of him: don't think they are rare or new for you, but just in case you can see them here:
http://photo.newyork.ru/thumbnails.php?album=354Millionnaya 3 – I think you are right and there are some confusions. It’s very difficult to find out what exact address the documents refer to when it concerns Millionnaya and Dvortsovaya. The problem is that there always has been a confusion between houses on the embankment and Millionnaya, because in many cases the parcels of land for the construction were limited by both. My title for the apartments on Millionnaya reads (and therefore the official address of apartments, which face Millionnaya only) is Millionnaya _house number_-Dvortsovaya_house number_. Actually, this address includes: a building on Millionnaya, a building on Dvortsovaya and a few buildings between them in the yard. I meant just to mention the fact that the British Embassy was in the Saltikov house at the time of revolution and until those awful events in August 1918.
When in August 1828 The St. Petersburg Vedomosty made an announcement it stated that “stone building… facing the embankment and the Suvorov Square, including all furniture, bronze items, marble items and other decorations” is for rent. It’s known that Saltikov lived on Millionnaya again in 1870, but at the same time he owned a big country estate Chernevo in Pskov (?) region and invested a lot into its development and reconstruction. In 1986 he became the owner of a cottage on Chernaya Rechka in St. Petersburg and a big house on Stroganovskaya Street.