Yesterday I replaced my drop-in filter and my air cabin filter with OEM Toyota ones. My goodness that drop-in filter wasn't "drop-in" at all. A PITA. I think now that I have a better understanding of how it's replaced, though, that it'll truly be "drop-in" next time. You should just be able to unlatch and swap filters. No clue why there's a DIY to unbolt the air box and slide them apart and together.
I realized I was just putting it in backwards...
Otherwise I don't think I would've needed to pull apart the air box from the snorkel and such. Ah well. This is why it's fun to work on your own car. Now I know how to swap it myself!