FCS has no advantages in recruiting when going up against the FBS schools. I suppose individual universities have there own policies as to selective admission. McNeese has gone to selective admissions and have actually seen the programs improve. Most kids want to go to FBS so the FCS becomes a hard sell.
For the bigger schools like LSU, they just pick up the tab and enroll the prospect into a JUCO or Hargrave Military Academy "to get qualified". That's what they did to Kieland Williams. I think Ole Miss sued the NCAA under the Americans with Disabilites Act to finally get Gerald Powe into the university and he can't read!
Where McNeese fell short was in the APR (Academic Progress Rate) which was inherired from the previous coaching regime. I think if the NCAA was strictly enforcing the APR during Baldwin's tenure it was going to be ugly. Thank God those days are gone.
At the end of the day most universities without the financial clout "grey-shirt" a recruit until they qualify. They come on their own dime and see if the they can succeed academically. It seems to work better for the school and the athlete.