Perhaps you could proactively address #3 now by using their sympathy to get them to write you a short 'recommendation' or vouch for the fact that they accepted you for their internship program, so that in the future on your LinkedIn you can note the summer of 2020 as the headline 'Internship at ______ - canceled due to Corona - instead I taught myself _____', and then in the body of that entry, start with their quote they gave about what impressed them about you, and then write the rest of the entry about what other stuff you learned / did instead.
you forgot one very important item: full time offer.
Finally, I found something for the city doing data entry. The salary was poverty-line level. I drove down the morning it was supposed to begin, but the door was locked. I got home and checked my voicemail - they canceled the position.
I had a decent business idea or two, and ended up becoming an entrepreneur out of just frustration really, and within six months I had meetings with executives of businesses I couldn't get an internship with about partnerships.
Just keep working and solving problems.
honestly i feel that a lot. if my internship gets cancelled i'll be mighty disappointed after having anticipated it for so long (years) but one thing you should (and i will) keep in mind is that you can probably get recycled to next summer. admittedly that isn't a consolation if you're graduating next year.