The IRS decides whether or not to allow your credit. No one here can tell you whether or not the IRS will ask for additional documentation.
As far as delays, this year *ALL* returns claiming EITC are by law delayed till at least February 15, and the IRS says not to expect refunds with EITC before the week of February 27. Your need to file an 8862 may delay it further, but again no one here can say how much longer; that is entirely up to the IRS.
