By Doug Vazquez,Justin Barrasso Best bets for UFC 280, headlined by SI Sportsbook favorite Islam Makhachev fighting Charles Oliveira. The UFC returns to Fight Island in Abu Dhabi for a card that features two title fights amongst a slew of high-level scraps from top to bottom. In the co-main event, bantamweight champion Aljamain Sterling will defend his belt against the former champion TJ Dillashaw. In the main event, we will finally get an official champion in the lightweight division as the former title holder Charles Oliveira will look to reclaim the belt he was stripped of after missing wei…