Since so many have died from Dragon pox in the past, I don't think there is a simple fix.

Lots of quarantine and cleaning, to say the least.

I think they will send students back to their house first and send the patients to st. mungo's

Protego Coronaxima!

Man, I tell you. This is quite the question. They would probably go home and use some mirror portal cast by their wands that is like Google meets but for wizards. They Probly have books and everything waiting for them and they probly asked the ministry to have only certain spells that

The students can cast.

Yeah they'd probably use some sort of magical communication method for class (like a magical Zoom).

Coronavirus is a muggle virus. Basically wizards can cure any muggle sickness but not a magic sickness like dragon pox. I Th ink they would cure it quickly and they wouldn’t have to close school.

Hogwarts would have been safe for half bloods and muggle borns

St Mungo’s and ministry

I think Madam Pomfrey may get excessively overworked.