The biggest ones:
The interior defensive line. Who would fill the rather large shoes of departed nose guard Tommy Jackson and departed defensive tackle Wayne Dickens?
Wide receiver. Who would earn their spurs alongside senior Courtney Taylor, the obvious bellcow?
Safety. Who would emerge from the crowded field of talented but mostly inexperienced players?
Newbies. Which freshmen would show themselves ready for SEC competition?
After one practice in full gear and two in shorts and shoulder pads, there are not yet any definitive answers, of course. But there are some significant signs.
Not so long ago, nobody would have given good odds that either would still be around. Doolittle almost left the team in 2004. Sims left after the second game of last season, but returned at season's end. Both began to make moves in spring practice. They have made even bigger moves in the past week.
Doolittle has eased worries about having a solid backup for senior Josh Thompson and, with a new attitude and better strength and conditioning, put himself in position to get significant playing time.
Sims, with NFL talent, looks to be on his way to turning around a career that seemed to be over last September. At the end of practice Sunday, he had moved ahead of senior Chris Browder and was running with the first unit. Whether he stays there or plays as a backup, his emergence could solidify the defensive interior.
Pat Sims (95) played well in spring drills and has continued to improve in the first week of August practices.
Thompson, Browder, Sims, Doolittle and redshirt freshman Sen'Derrick Marks would probably make up the rotation inside if the season started today.
Though they probably wouldn't agree, that's good news for one of the more impressive classes of defensive tackles Auburn has signed in recent years. Bart Eddins, Jermarcus Ricks, Mike Blanc and Byron Isom could all be redshirted.
Virtually every college football freshman is better off being redshirted. That is particularly true for linemen. It's not easy for an 18-year-old just out of high school to play against the grown men who play in the Southeastern Conference trenches.
At linebacker, Willis went into preseason practice with a far more difficult job than he anticipated leaving spring practice.
Blackmon was the projected starter on the weak side. Sears could play any of the three positions, and at 240-plus pounds, was being groomed to spend significant time in the middle.
Sears could be gone for three games. Blackmon could be gone for even longer. That leaves senior Karibi Dede as the only linebacker who has ever started a game at the position.
In Sunday's full-gear practice, converted safety Will Herring was first-teamer on the strong side as he has been since making the move last spring. But sophomore Merrill Johnson, who moved over from the weak side, was the first-teamer in the middle and true freshman Craig Stevens was on the weak side.
Don't expect that to be the way the Tigers line up on Sept. 2 against Washington State.
Dede, barring something totally unexpected, will be the starter in the middle, though he could see time at any of the three positions. Herring is locked in on the strong side. The real question is who will start on the weak side.
Steve Gandy, the starting strong safety at the end of last season, was getting most of the first-team reps on the weak side before he suffered a bruised quad. Willis moved sophomore Merrill Johnson from the weak side to the middle. That's a move Auburn coaches seem to like, but it's not realistic to believe that Johnson will beat out Dede or that Stevens will stay ahead of Gandy.
My guess is that the starters against Washington State will be Dede in the middle and Herring and Gandy on the outside. That's quite interesting, because all three have not only played safety, but have been starters at safety in their careers.
That's good from the standpoint of speed and athleticism, not so good from the standpoint of size. Auburn might have the fastest linebacker corps in the SEC. It also might have the smallest. What that means remains to be seen.
At wide receiver, freshman Tim Hawthorne seems to be as talented as advertised and should get some playing time. Taylor is healthy and ready to finish his career in style. Junior Prechae Rodriguez will probably be next in line behind Taylor in the wide receiver pecking order. After that, nothing is certain.
Watching senior Lee Guess run precise routes and catch every ball that is close to him leads me to believe he should get ample playing time at the slot receiver. But I felt the same way last year and it didn't happen.
Offensive coordinator Al Borges has had significant praise for walk-on sophomore Rodgeriqus Smith. There's no way to know who will emerge from the crowd that includes redshirt freshman Montez Billings, sophomore Robert Dunn, sophomore Anthony Campbell and true freshman Terrell Zachary.
The top three after five days, to these untrained eyes, are Taylor, Rodriguez and Guess, with Smith not far behind.
Rodgeriqus Smith (21) is shown in Sunday's practice after catching a pass.
At safety, nothing seems to have been answered yet. Will Muschamp, the defensive coordinator and secondary coach, holds his cards close. If he has an idea who will start against Washington State, he's not saying.
Brock was the starter at strong safety last season before losing his job to Gandy. He seems to be more mature. He certainly has what it takes physically. Savage left spring practice as a starter, but Davis, immensely talented, is pushing hard.
My guess is that, in the end, Brock will be the starter at strong safety, with Ferguson backing him up. The race between Savage and Davis at free safety is too close to call.
In the big picture, there's not a lot of playing time available for the incoming freshmen class. That speaks to the depth and talent in Auburn's program.
It appears that Hawthorne, Stevens and tight end Michael Goggans are likely to get playing time. Running back Ben Tate, who was on campus for spring practice, is fighting for a spot in one of the deeper backfields ever at Auburn. Zachary is in the hunt at wide receiver.
Running back Mario Fannin is certainly physically mature enough and talented enough to play. But there might simply be too many players ahead of him.
Zach Clayton has gotten plenty of action at defensive end and could figure into the plans.
It is, of course, still very early in the process of building a football team. A lot can and will happen between now and Sept. 2.