I like how you represented the Eastern Belarusian provinces, but there are still are lot of things I would like to point, basing on the date of the Imperial census of 1897, and which are needed to be fixed.
First of all regarding Vilna and Molodechno region. It is quite strange that the regions are mainly Lithuanian, when in fact they were already much slavinized in the 19th century. The data of the census in the Vilna gubernia says there were:
56,2 % Belarusians
17,6 % Lithuanians
12,6 % Jews
8,2 % Poles
4,9 % Russians
0,2 % Germans
0,1 % Ukrainians
0,1 % Tatars
0,1 % Others
In the Vilna uyezd (district), which are resented by Vilna province in game itself:
63,0 % Belarusians
19,8 % Lithuanians
8,4 % Jews
5,6 % Poles
3,0 % Russians
0,2 % Others
And according to the results only in the city itself (only urban population):
40,0 % Jews
30,1 % Poles
20,9 % Russians
4,3 % Belarusians
2,1 % Lithuanians
1,4 % Germans
0,5 % Tatars
0,3 % Ukrainains
0,4 % Others
The all urban population of the Vilna district:
53,8 % Jews
19,6 % Belarusians
11,9 % Russians
11,5 % Poles
1,2 % Tatars
1,0 % Lithuanians
0,4 % Ukrainians
0,2 % Germans
0,4 % Others
http://img126.imageshack.us/img126/7826/69jg.gif
So as you see the majority of the province population should be Belarusians with large Lithuanian minority (both as mainly peasants, and only some very small groups Belarusians as clerks or craftsmen may be). Jews should represent majority of the craftsmen and clerks, Russians – mainly clerks and officers, Poles – aristocrats, capitalists, clerks.
The common number of the district population in the district is 363.313 people. By the religion they are:
Catholics: 237.375
Jews: 79.360
Orthodox: 36.462
Old-believers (Orthodox): 4.989
Lutherans: 2.558
Mohammedans (Muslims): 981
Calvinists: 139
Karaites (Muslims): 86
And several dozens of others
By the social strata there were (Vilna district
without Vilna city itself – 208.781):
Peasants: 170.755
Townspeople (clerks and craftsmen): 33.148
Nobles: 9.513
Personal nobles and non-noble officials (clerks): 340
The privileged burgers and merchants (capitalists): 136
Priests: 109
Several hundreds others (poor, foreigners etc)
And you should add to it also Vilna city itself – 154.532:
Townspeople: 86.806
Peasants: 41.734
Nobles: 15.293
Personal nobles and non-noble officials (clerks): 4.832
The privileged burgers and merchants (capitalists): 2.838
Priests: 979
Others
And of course don’t forget to add some soldiers naturally.
Similar social strata could be used for other Belarusian region, except there were less clerks and craftsmen in most regions (may be only many in Vitebsk).
Then concerning the ethnic groups of Molodechno region (the Oshmiany district).
Oshmyanski district (233.558 people) according to language:
Belarusian: 186.733
Lithuanian: 8.754
Russian: 5.472
Polish: 4.070
Germans: 58
Others
So, as you see Lithuanians were in the 19th century here only a minority.
And as soon as there is no “Jewish language” definition in census in this case, the religion data can help here:
Oshmyanski uyezd according to religion:
Catholics: 132.505
Orthodox: 71.379
Jews: 28.244
Mohammedans (Muslims): 788
Old-believers (Orthodox): 519
Lutherans: 65
Others
Also some data concerning Glybokaye province (Vileyski uyezd). Vileyski uyezd (208.013 people) according to language:
Belarusian: 180.695
Polish: 5.100
Russian: 1.932
Lithuanian: 121
German: 30
Others
Vileyski uyezd according to religion:
Orthodox: 121.551
Catholics: 65.558
Jews: 19.826
Old-believers (Orthodox): 531
Mohammedans (Muslims): 405
Lutherans: 88
Others