If you’re worried about an emergency situation where you might have to make do with whatever cells you can find, I would suggest that you consider having two lights: one light that takes 3×AA or 4×AA, and a second light that takes 1×AA.
That way, if you only have one cell, you can still use the 1×AA light. If you have 3 or 4 cells, you can use the larger light for higher efficiency and access to higher light output (if you need it).
Efficiency is especially relevant with alkaline cells, because the boost driver in a 1×AA light trades current for voltage - it has to draw more current at the input to get more voltage at the output. That’s about the worst thing you can do with an alkaline cell, because its high internal resistance will cause its voltage to drop at higher current, so the driver needs even more current, which causes the cell voltage to drop still further, and so on into a vicious circle. NiMH cells and lithium cells are much less prone to this effect.
I would strongly recommend avoiding alkaline cells unless it really is an emergency, because of the risk that they will leak.
My advice is to put Eneloop NiMH in both lights, with an unopened pack of 1.5V Energizer Ultimate Lithium primary cells in a Ziploc bag stored next to each light. That way, the lights are ready for use, and you have a set of long shelf life cells ready as a backup.
Swap the Eneloops for a fresh set once a year, as a “belt and braces” precaution. They do hold a charge for up to 10 years, but there’s always an outside chance that even the best quality product might fail on you. It’s a fact of life that nothing’s perfect.
Steer clear of lights that take more than 4 AA cells, unless they can be used with a partial set. You might not be able to get your hands on 6 or 8 AAs at once in an emergency. For example, I have an old Fenix TK41, which is an 8×AA light, but I’m fine with that because it can run on 4×AA if necessary.