I don't see it that way.
Sure Smith should be the first choice. He is the most prolific scorer out of the bunch. Either from downtown or at the rim. However because he's restricted, the "rich-n-creamies" could decide to match any offer for him. Or perhaps another team may decide to simply outbid them.
Azibuke strikes me as a guy GS would be willing to retain. Besides, I believe he's a RFA too. If so, GS could match.
Barnes isn't a prolific enough of a scorer.
Jones is an UFA, yet merely a spot-up shooter.
Dorell Wright is a talented player, but more of a defensive player at this point in his career. He simply doesn't score enough.
I've completed forgot about Artest as a possible option. He may be in demand as much as Smith. If his salary demands are in line, I'd be OK with him. Even though he's a potential loose cannon. If the Spurs were to indeed land Artest, the West would easily be won.
The second best option is Pietrus. He has all the components and skill that the Spurs need in a potential starting or subs ute 2-guard. Scoring, rebounding, defense, athleticism. I believe with the infrastructure the Spurs have in place, along with the the instructional coaching, he'd be an ideal fit.