At the moment, no. The rejection letter is written to the authors, and I think that most authors would be mortified if their rejection letters were made available. At that point the authors can attempt to send it to another journal. There is nothing stopping the authors of this paper from publishing the peer-reviewed comments and feedback they will have received from attempting to publish it.

I don't know what PlosOne's policy on publishing something like this would be. They don't reject based on relevance or impact alone, but I suspect that they would not want anything that looked fraudulent in their journal nonetheless.

Maybe even more troubling than the potential that the virus is engineered. It's that why are American institutions trying to limit distribution on a scientific literature just because of the literature's implications? Chilling...

The sequenced genome is freely available to all to look at, and compare to other genomes. While gene editing is not my field, if SARS-Cov-2 looked obviously man-made, I don't think any single institution / country could stop an international community of scientists from talking about this. If the evidence of gene editing is more subtle, I suspect it will simply come out in time.

Also, there is already a paper looking at whether sars-cov-2 is man-made, published in one of the most prestigious scientific journals in the world (not American):

https://www.nature.com/articles/s41591-020-0820-9