To my responders, it's great to see such interest and support! I could definitely make better instructions on how to use this.
I actually only recently got this plugin fully working, but then I ended up merging it with a much larger "Equipment" plugin I'm working on (which is also free and open source, though not finished yet).
The big thing that kept me from making this plugin usable for my use-case was that I wanted users to be redirected to the phone verification page if their phone had not yet been verified, but this should not happen with every user; only with users assigned with the role of "Parent" to another user, i.e. their students. Parents need to verify their phones; students do not. Thinking long-term for my company, theoretically, parents could be students and students could be parents. Because of this possibility, I had to figure out how to differentiate different types of user accounts. I found one way, though it's not the best.
Anyway, the plugin should actually still be working, but users must go to the phone verification page to verify their phones manually. My Equipment plugin may be worth checking out when it's done, but it's a big boy, and I'm only 1 person, so it'll have a good amount of flaws, and some dirty code.