OMAHA, Neb. — A day before their teams were to meet for the first game of the College World Series finals, LSU coach Paul Mainieri and Florida coach Kevin O’Sullivan stood side-by-side and smiled for the cameras. On the dais between them sat the NCAA national championship trophy — a relatively plain-looking tower of lucite and wood they have nevertheless spent the past several months working and yearning for. The photo-op dragged on, their smiles remained. A reporter interrupted. This feels awkward, the guy said. “It’s not awkward,” Mainieri said. “We like each other.” Friends indeed, for at least this day. Distant cousins, in a way. The two coaches know plenty about each other, as do their teams.