[stupac2]

If all their kids have already got covid, no reason schools can't open.

*envision guy tapping head meme here*

You probably meant this rhetorically, but isn't  it, in its perverse way, good news?

That was my first thought, but keep in mind that there is selection bias going on here; children are presumably only being tested if they are symptomatic or close contacts of someone infected.  If there were a random sample of children in the state, then you might think that in the next two months you could get to herd immunity and safely open the schools.  Alas, I suspect the fraction of kids who are not tested who would be positive if they had been, is a lot lower than 30% so we are probably a ways away from herd immunity.

BC

Right, unless you think there's a reason for, during summer break, kids to be more likely to get it than adults (if anything the opposite seems more likely), this would imply that FL has ~6.5M cases (confirmed is ~300k) and that there should be ~30k total deaths (assuming 0.5% IFR), when there are only 4700 currently. Yeah, deaths lag, but not by that much. 
This is selection bias, and not what you should expect to see for the overall population.

[stupac2]

If all their kids have already got covid, no reason schools can't open.

*envision guy tapping head meme here*

You probably meant this rhetorically, but isn't  it, in its perverse way, good news?

That was my first thought, but keep in mind that there is selection bias going on here; children are presumably only being tested if they are symptomatic or close contacts of someone infected.  If there were a random sample of children in the state, then you might think that in the next two months you could get to herd immunity and safely open the schools.  Alas, I suspect the fraction of kids who are not tested who would be positive if they had been, is a lot lower than 30% so we are probably a ways away from herd immunity.

BC

Right, unless you think there's a reason for, during summer break, kids to be more likely to get it than adults (if anything the opposite seems more likely), this would imply that FL has ~6.5M cases (confirmed is ~300k) and that there should be ~30k total deaths (assuming 0.5% IFR), when there are only 4700 currently. Yeah, deaths lag, but not by that much. 
This is selection bias, and not what you should expect to see for the overall population.