One of the five Titans fans here in Iowa, so I actually follow this pretty closely. Leading up to training camp, there was a lot of optimism that Akrum would supplant Fluellen as the #3 RB. The brakes have been pumped on that a bit, as thus far, he has not been able to get past taking #4 reps. However, there still seems to be a good chance of this happening. Conventional wisdom is currently that they will carry 4 RB, but things can change.
Regarding the idea of him becoming the featured 3rd down back, I just don't see that happening unless Dion Lewis gets hurt or significantly under performs. Lewis is very good out of the backfield and has a lot more experience. In addition to that, people don't realize how good Derrick Henry's hands are. Put those things together, and barring injury, I only see spot duty on offense.
Punt return game, with Adoree' Jackson being very good, I just don't see it. His better chance to show off his skills could come in the kick return game (still likely as secondary returner behind Jackson, unless they want to lighten Jackson's load). If he shines there, then maybe he sees a few more plays on offense.