Gute voch, 1. A question about the Kever in Uman. As you know, the Shul where Rabbi Nahman is burried was an old jewish cemetery, and later the soviets built houses there so hard to tell where is really lines and graves of the old cemetary. But the question remains, can Cohanim enter the area and walk there or daven or study? What about eating? Also Can both men and women learn or pray in the same synagogue where the only separation is a carton wall, and they can hear each other's voices? 2. Can people eat at old cemetaries if there is no sign of a Matzeva but you know that is jewish old cemetary 3. What were main. difference between synanogues in Ukraine that you may know about?
ב"ה Shalom Shalom I personally have never been to Uman, but so many thousands of others have been there. Among them, I am sure there were important Rabbis who probably defined the areas where Cohanim may go and may not go. This is not something I can answer, from a distance. If there is a proper separation between men and women men and women may pray in the same synagogue, it is fine even if the wall is carton. If the women are not singing, there is no problem hearing women pray. 2. The Shulcha Aruch states, we do not act disrespectfully in a cemetery. Therefore, one may not eat there. However, if a distance is kept from the burial sites, one may eat. Again, in the circumstances you describe one would have to consult with the local Rabbis to show where one may eat. 3. . I am not familiar with the synagogues in the Ukraine. All the best