Mariage avec ressortissant russe

Please could you help me with the following ? I plan to marry with a Russian. But I get different versions of how to do it, it's difficult to get the information in one time. As far as I know at that moment, the Commune is requesting the next documents :
- "svidetelstva o rozhdenii"
- certificate of redisdence
- certificate of nationality
- "certificat de célibat"
- "certificat de coutume"
As told in the Commune these documents have to been issued in Russia, translate into French ans legalized by the Belgian Consulate in Moscow.... But as far as I heard by another hand, only 2 documents have to been issued in Russia and not legalized by the Belgian consulate, but have to be with the apostille. Do you know how to really do to get these documents available in Belgium with the apostille. Can the Russian Consulate in Belgium provide some of these documents and are they reliable for the Belgian authorities ?
Another question is about the way of getting to Belgium, we plan to apply for a short term visa of 90 days and marry during that period. What happen after the marriage, does the spouse receive the right to stay in Belgium automatically ?
I thank you in advance for your answers, you can answer in English, Russian or French.