Q1) IMO too many unknowns to answer accurately since we don't even have a good idea of how many folks in the US are already infected (1M? 5M? more?) since this began and thus how many more might be infected in a given month with reduced social distancing. Moreover, there's still a lively debate as to how much immunity even exists in recovered patients. It's quite possible herd immunity (and/or a vaccine) many never be achievable with this virus.

Q2) Are you suggesting patients that do not seek hospitalization would self administer at home or that there is some other indirect symptom reduction in some people by treating others? Presuming the latter, I'd expect a spike of potentially severe cases to occur soon after relaxed social distancing since the current theory is that folks exhibiting no symptoms are the main spreaders rather than the moderately/severely ill, regardless of how they're being treated.
Is 3M doses/month enough to mitigate this spike? Really hard to say due to the lack of infection data outlined in Q1.