No. When he looked into the mirror he could definitely not see Ham. Please have a look at the many drivers eye videos, they look over the rear wheel. Ham was quite far away from the field of view.
Can you see the slip effect for the RedBulls? Perez had to lift strongly. Either both Mercs block right or left. They blocked the inside, which was the natural way to do. You do not give up the inside. In the worst case with Bot moving left, Ver would have been between before Ham can cover it...Ver with slipstream well ahead in the first corner.
No. This is why it is so strange that people think giving up the inside line would be a solution. Bottas would have never done this line. Bottas would have just drowned on the outside, most probably with grass under his wheels.
With Ham giving up the inside for Per, we would have had maybe Per-Ham-Ver in this case. Much worse situation.