At this point, the team can just go BPA...
They may like Fleener because it gives the Niners another RZ threat, a guy who already knows the offense, and someone they could plug in immediately.
They might also look to add some depth to their DL since J Smith will be 33 next year...and because this draft is particularly well stocked with good DLmen. There should be a very good one available at pick 30.
The Niners will NOT draft a guard in the first round because of the financial commitment at that position. Iupati already makes a boatload of money and they will have to re-sign him at some point.
I also doubt the team will draft a CB in the first 2-3 rounds since they just added 2 vets to the roster.
However, if a top 20 pick falls to them at 30, regardless of position, they are now set to pull the trigger....and that how good teams continue to be good teams.