HI,
What I now know, I learned from reading Wikipedia, who also highlighted the bread and European-style sausages.
On the dark side of history, Harbin Russians who returned to the USSR during the 1930's as well as those post World War II, we're considered suspect and put to gulags. Many Harbin Russians were anti-Communist, though those were the ones likely not to return. It also may indicate why this pocket of ex-pat's may not be widely known. If you were associated with them, it could mean trouble for you.
The internet is always full of surprises, I will keep my eyes open and advise whatever I may learn. Maybe your friend's family and friends in Harbin might be a source of recipes. Of course, if you are trying to launch a surprise, this source may not be immediately available.
I just asked my Dad who vaguely remembered Harbin being near Vladovostok, then I mentioned the railroad. The bells went off, because Harbin is a border town from Russia into China. He hasn't personally been there, though he knew people who traveled that route.
Regards,