I believe Alan McElroy and Vaun Wilmott (who co-wrote the "New Eden" episode) were added due to previous religious related writing they had done.
In one interview Kurtzman was asked about new writers on the staff and he seem very high on Michelle Paradise. She is listed (on IMDB) as co-writer (along with Kurtzman and Jenny Lumet) for the last 2 episodes of he season. So the season finale may be a two parter. When they increased from 13 to 14 episode it may have been to expand the season finale.
In one interview Kurtzman was asked about new writers on the staff and he seem very high on Michelle Paradise. She is listed (on IMDB) as co-writer (along with Kurtzman and Jenny Lumet) for the last 2 episodes of he season. So the season finale may be a two parter. When they increased from 13 to 14 episode it may have been to expand the season finale.