I'm not sure of the amount that will be invited or that will try to walk-on, but the squad size has to be reduced to 105 by September 1 (correct me if I'm wrong on the numbers). That means with 85 scholarshipped, there are twenty or so walk-ons in the fall. I think the walk-on roster expands in the spring as seniors leave and numbers are needed for spring drills.
Not sure about paticular walk-ons. I'm sure we'll have kickers and punters, as that is normal. I've heard about Michael DeJohn from Hoover possible walking-on, and Chris Smith has been mentioned. Other than that, I have no idea.