#2 is debatable. It wouldnt need to spread from surface to mask. It would also be able to spread via captured droplets. The mask is filtering the ir, this means a high degree of infected droplets are constantly being captured by the mask.
To #1 Id say the increase is overwhelming. Normally with a mask every sip of your drink you must touch the mask and usually incidentally your face, something you wouldn't do without a mask,.
#2 we covered.
#3 is not entierly true either. even if the lower spread to the environment was significant, but non-zero, it can easily be offset and reversed by a significant increase in your ability to be infected yourself.