No. When submitting you have to confirm that the manuscript had not been submitted to any other journal. You may withdraw and submit to a better journal after the comments, but it's the other story.
That is not a good practice because time is spent in processing papers, no journal editor will be happy to know that the paper he is struggling to read has also arrived the table of another simulteneouslly. It is better to submit to one journal and wait for result .
No. You are not supposed to submit your work to several journals at the same time. You should carefully choose the best journal for your paper scope, submit to it, and wait for the result. If your paper get rejected, you can always improve it based on the reviewers comments and submit it to other journal.
No. When submitting you have to confirm that the manuscript had not been submitted to any other journal. You may withdraw and submit to a better journal after the comments, but it's the other story.