I had the same idea. But, the problem you'll have with those tower fans is that the on/off/speed and oscillator control are electronic switches connected to a little computer. If you have an interruption of power the fan will not resume operation until you press those on/off and oscillator switches again.
I took a couple fans apart and it is possible to cut some wires and attach them to ordinary toggle switches. I don't think it's worth the effort. I ended up putting a large'ish circular fan at the top of the tent blowing down and sweeping side to side.
If you really want to make a tower fan work so that it stays on even after a power interruption, you also have to be concerned with how the fan's motor speed is controlled. Some fans use "dimmer" like electronics internally to control the speed. That's nearly impossible to bypass to an ordinary toggle switch and also have speed control. If you're lucky, the fan will use a motor with different windings for each speed. Each speed has a dedicated wire. In that case, each wire can be cut and attached to a toggle or rotary switch.
I did this to a couple small Lasko 4000 "air stick" desktop tower fans. I considered doing it to full-size Holmes HT-38R (which I confirmed uses motor windings). But, mounting a
full-size Lasko 3012 rotary fan up high seemed easier -- and saved floor space. I used a couple U bolts through a piece of 1x4 wood, about 10" long. The U bolts grip the tent leg, clamping the wood onto the tent leg. The 1x4 is then a flat surface to mount the fan.
Note: If you take the time to oil even the cheapest fan, it will last forever. Cheap fans are usually not oiled when assembled by the factory. They wear out quick. A couple drops of oil on the bushing makes a huge difference. Zoom Spout oil (google for it) has a long retractable applicator which makes it easy to apply oil without disassembling ordinary rotary fans. Apply every 4-6 months if using a fan 24x7. If you can get better access to the bearing surfaces, heavier grease (wheel bearing grease at the auto store) lasts longer. I did that with the Lasko "air stick" fans when I had them apart.
I live in a hot climate and use fans a lot. That's why I make a bigger thing out of lubrication.