Your advice seems optimized for... well, adults. Sure, if you can use your income as a metric, or your expenses, or some other way of measuring your financial situation - great.

Donating a fixed percentage of your income, then doing as you normally would if you had only gotten this reduced income in the first place, can apply to almost everyone. (People like you who don't have an income have other problems.)

Saving is a very good idea - actually, my idea of "financial security" is "being able to save money". It's just not compatible with the "starving undergrad" model. I'm not a responsible adult, I'm a crazy kid. I don't do responsibility. Sure, when I get a job (and it'll likely be high-paying) I'll start saving (also a fixed percentage, at least until I get the hang of things).

Prioritizing saving and vaguely defined necessary expenses... that's what I'm afraid of. If I say "I'll wait until I have enough savings to live on for six months", I'll just spend a little more every month, notice I haven't saved enough yet, and wait a little more. If I say "I'll wait until I can reliably pay the bills and track spending and get necessities like insurance", I'll just keep moving the goalposts - I'll start thinking I need a car, and I might get sick so I need to save more, and I'll have a big crash and drop accounting for six months.