I had trouble finding a list on the official site other than the December 2014 signees. Rivals did have a signee list combining the December 2014 and Spring 2015 signees. The Rivals list I have found linked below has 23 signees. 7 played a lot, 7 played a little, and 9 played very little or not at all. 10 were JC transfers. 5 of the JC transfers played a lot, 3 played a little, and 2 played little or not at all. If my memory is correct, 2 freshman signees played 4 years with no red-shirt and finished playing after the 2018 season. Only 2 freshman signees were still around to play on the 2019 team, Drake Dorbeck and Ty Pollard.
https://southernmiss.com/news/2014/12/17/Football_Inks_Eight_on_JuCo_Signing_Day.aspx
https://southernmiss.rivals.com/commitments/football/2015
https://southernmiss.com/news/2014/12/17/Football_Inks_Eight_on_JuCo_Signing_Day.aspx
https://southernmiss.rivals.com/commitments/football/2015
