Thanks for the feedback, all.
I read the CP forum entries of spectacular lithium battery failures with some alarm. However, a search seems to reveal that most if not all of these issues seem to be associated with CR123As, a type already considered and rejected for my application (not the right size to fit available tubing, for one thing). I can find no mention of malfunctions associated with the EverReady AA lithiums. If I missed some that y'all are aware of, please let me know. Those threads were enough to make me scrap my CR123A flashlights, though. :-/
However, I know the chemistry is the same so I need to be concerned. Fortunately, my design already accounts for catastrophic explosion in that while the tube is solid and sealed on one end with a solid aluminum plug, the other end is a tight sip fit into a plastic housing with a thin plastic barrier sealing the opening in the housing and the tube retained with a pair of set screws. These features weren't intended as a "blowout" feature for an overpressure situation but should serve nicely. Also, the tube would tend to pop out of the housing before pressure got anywhere near enough to burst the tube, in any case.
I am continuing my research. Thanks again.