It can happen if Russia says Medvedeva zagitova and sotskova are team but ioc panel says zagitova doesn’t have enough tests to prove she’s clean. So zagitova has to be removed. Russia then says pogorilaya but it’s after a deadline and she can’t be cleared. But that still wouldn’t mean another country gets the spot. People are far too sure the panel will allow all Russian skaters. You don’t know if they might want 5 years of tests. So maybe only leonova will be eligible?
I'm pretty sure the top 3 at nationals are those who will go and pass all required tests. In case you didn't notice, the IOC is doing everything to make the ban as 'least uncomfortable' as possible for the clean athletes - they chose to name them 'olympic athletes from russia' instead of just 'neutral athletes', they announced the decision in the evening in russia, so that Putin could wait until the next day and until things were a little calmed down, to state that athletes are allowed to go. They are giving these neutral athletes a uniform to wear and the designs are already in work - and if the Russian deputy FM says the color of that uniform will be red, white and blue, then it's a strong indication that he has seen them.
all in all it's pretty obvious, that Bach had a talk with Putin and while the ban was inevitable, they did talk about how to make things easier and what can be acceptable for them both ...
