A few thoughts if I may.
I respect the use of AAA vs 18650, but in the end an AA battery/light will be a better purchase and output.
Regarding battery disposal of non-rechargabale batteries I also thought it was bad to dispose of them into the garbage. I do know that
the problems in the past was mercury/lead that was used and now is no longer used or sold in the USA/Canada. The major battery companies
Eveready, Duracell say just toss the NON-rechargables.

Lasly, if you do choose to use NON-rechargable be aware that the cheapo batteries, Costco, CVS, Walmart brands will never last as long as a better quality battery. With 3 batteries being used each time, if one is bad the group of 3 are tossed. Perhaps again an AA single light will be a more prudent investment.

Robert