The heritage museum in Mokrin can give you information about mentions of your family in village history books, property and merchant records, their status and involvement in local village organization, location of ancestral home, headstones that exist in the local cemetery. However, they do not have the vital records - civil vital records are kept by municipal offices.
Church vital records - the original books- of all religions have been returned by the state of Serbia last year to its original authors - in your case, that would be the Roman Catholic diocese that includes the temple where your ancestors were baptized&married. Contact them directly and ask for help and information - remember, reasonable donation to the church you are contacting is a customary thing over here that makes receiving answers easier.http://www.catholic-zr.org.rs/eng/eng.html
The original church vital records have also been microfilmed by the historical archives and are available to be viewed and researched in the archives in Serbia.
I see no listing of Roman Catholic vital records or microfilms in the Kikinda archive, but you need to contact them and ask specifically - all websites and listings of archival collections in Serbia are in dire need of updating. :)
Archive in Kikinda have records of the Roman Catholic schools for Kikinda and Mokrin, which will have info on your ancestors - for every student, a personal entry would include names of parents, address, birth year, and school reports.
Also of interest if your ancestors migrated to the area during the Austro-Hungarian land reforms would be their collection of the colonization documents 1849-1871.
Serbian Genealogy Society SGS "Rodoslovlje"http://www.rodoslovlje.com/en