HOUSTON — It’s been more than seven months since the Texas Legislature passed a bill allowing public schools to hire school chaplains, but for the Rev. Dave Welch, his work has just begun. Dining last month at the Taste of Texas, a sprawling restaurant and museum on the outskirts of Houston with 750-pound replica cannons made to resemble those from the Battle of the Alamo bolted to its entryway, the longtime conservative Christian activist outlined his two-pronged plan for what comes next.