On mobile I’d suggest Fennec instead of stock Firefox since you can use add-ons without limitation, and don’t need workarounds such as the Firefox nightly.
It’s basically stock with enabled add-ons, and following the official release cycle with 2-3 days delay. Maintained by the original developers of the F-Droid store, so also a highly trustworthy source IMHO.
Using a dedicated browser should be good enough. Since you might need some proprietary google stuff, I’d suggest chromium portable, that way once the class is over, you can simply delete the whole folder and call it a day.