No. There's plenty of human mages. In fact, the raw numbers typically oughtweighs elves, by simple virtue of there's a stupid amount of humans everywhere. Depends entirely on your setting, I suppose, but humans are typically right in the mid-ground of magic capabilities, as they are for literally everything else. While there's usually more elf mages per capita, humanity still holds a large amount.
Besides, when talking military-wise, everyone's going to field mages. There's literally no reason not to field a mage in a squad. Even dwarves, of whom are like to have the lowest per-capita number of mages, will field mages. You've got to have at minimum one per squad. Mages are the equivalent of a multi-tool. Everyone is going to have one, just in case they need it.
Long-lasting enchantments to improve stamina are long-lasting enchantments you've wasted on that, what could've been used on something else.
As for cantrips, there's not many I can think of that'd help endurance or stamina. Of the ones I can think of, they require concentration. Enjoy the wasted concentration slot.
While true, we're talking a modern setting where radios are a thing. For intelligence on enemy movement that wouldn't be better suited by technology, you'd need something along the lines of scrying, which is fairly high-end, and usually requires some kind of connection with the target, be it a bit of hair or whathaveyou. Only other thing I can think would be an advantage would be some kind of life-vision type spell, which'd be easily met with simple thermals.
And of course none of this'll matter much when your enemy keeps on moving. Knowing where he was., while you've got to take a nap before attacking, isn't going to help you. Of course, this still leaves all the other issues I've mentioned, after contact, anyway. And all this is with the limitation to guerilla warfare, for whatever reason. Guerilla warfare is a means to weaken an enemy who's, effectively, already won. If you've got to rely on guerilla warfare, you're up shit creek as is. The idea behind it is basically make the enemy decide it costs to much, or weaken them to the point where you can mount an actual war.