As an epic, this has fallen into the realm of an overwrought Charlton Heston production, minus the sandals. Though the Celtics Hall of Fame room was furnished for a press conference to bid adieu to Doc Rivers, and for Danny Ainge to talk about his team’s very different future, by the end of yesterday afternoon television crews hurriedly packed up. Game 6 of the Stanley Cup finals pulled them all back to Causeway Street. As negotiations between the Celtics and Clippers groaned on, with no apparent finality in sight for the soon-to-be Clippers coach, eventually everyone was sent home. By 6 p.m. Ainge and Rivers would have faced reporters. Instead, discussion went late into last night about matters everyone thought were resolved. Final details reportedly had to be ironed out between Rivers and the Clippers, not the Celtics and Clippers. “Should have been done seven days ago,” a league source close to negotiations said of the machinations, and the experience of dealing with the notoriously difficult Clippers owner Donald Sterling. Was it a matter of paperwork, the three-hour time difference between Boston and Los Angeles, the price of doing business with Sterling, or something more irreparable? The NBA offices closed at 5 p.m., still waiting for an official filing of the proposal. Though the league is expected to step in with a Marvin Webster-sized rejection if these two teams come back with a bid to trade Kevin Garnett for DeAndre Jordan, approval of the Rivers business was expected to be a formality. But NBA commissioner David Stern can’t stamp something that hasn’t crossed his desk.