Voters will see three major contests on the ballots April 1 ballot — two for selectman and one for School Committee. Holbrook police Officer John Kearney is challenging incumbents Timothy Gordon and Matthew Moore in a three-way contest for two seats on the Board of Selectmen. To fill a one-year vacancy on the board, Robert Austin, a former selectman, is running against Daniel F. Moriarty III, son of the building inspector. For School Committee, incumbent Barbara Davis is joined by Stephen Gallagher, Arthur George, and Richard Stagnone in a contest for two seats; incumbent John Callahan is not running for re-election. Nomination papers were due Tuesday, but a contest for one of three Housing Authority seats was in question last week because one candidate did not appear to have enough verifiable signatures, said Town Clerk Jeanmarie Tarara.