Those are two aspects of it:
- The Rebbes approach to medical issues
- The Rebbes approach to major world events/dangers
You presented your case very well. But what would the Rebbe’s position/behavior be on masking, shul attendance, gatherings, weddings, etc etc.
I don't know, and I don't think anyone can say. There are multiple aspects to that question. There's the tevah of it, with regards to what the Rebbe would have seen about the realities of the pandemic and the risks that we may not be seeing. There's the legal aspect, where there are considerations about accommodating local laws and mandates. There's the ruchnius of it, where decisions need to be made about balancing physical safety and spiritual health.
A few examples that come to mind are the scuds in EY, Hurricane Andrew, Jews leaving South Africa, and the decades of Soviet oppression. The Rabbe's approach to each of those situations defied logic, because the Rebbe saw things no one else did. And in the case of Soviet Jewry, sometimes the spiritual benefits warranted physical risks. Given that small sample, which is really just the tip of the iceberg of the Rebbe's leadership, I don't see how anyone can begin to guess what the Rebbe would say here.