“The Bucket List” looks like Rob Reiner’s biggest wide opening ever — and his first success since “An American President” 13 long years ago — despite mostly poor reviews (Roger Ebert gave it one star) and being snubbed on the awards circuit. Based on early Friday figures, Steve Mason at Fantasy Moguls projects a $6 million opening day and $18.6 million over three days for the comedy starring Jack Nicholson and Morgan Freeman as terminal cancer patients. Even more surprising is the No. 2 showing for the low-budget Ice Cube heist caper “First Sunday,” which Mase tabs at $5.75 million for Friday and $15.25 for the three-day period. The greatly expanded “Bucket List” and “First Sunday” pushed “Juno,” which had occupied the No. 1 every day since last Sunday, into No. 3, dropping 20 percent to $4.25 million from last Friday despite adding another 500 screens. Not that anybody at Fox Searchlight will be complaining about the Oscar contender, which cost $12 million, crossing the $70 million mark the weekend ballots are cast. Another Oscar hopeful, “There Will Be Blood,” expanded to 127 locations and Mase projects a dazzling weekend average of $16,787 per venue.