Yes, they will.
They should fit, most iron sights are installed from the left.
No, it will not.
Just an update. I purchased these sights for my PPQ 45 . Installation was very easy for the front sight with proper tools . Rear sight was a little snug but did not require any fitting. Someone with a rear sight adjustment tool or a brass drift and light hammer would have no problem. On another note, once these sights have been charged with another light source, they are VERY bright !
No, it will not. Here is a link to a model that will:
https://www.opticsplanet.com/trijicon-bright-and-tough-3-dot-night-sights-walther-pps-wp02-c-600730.html
No, but either sets from the following 2 links will fit:
https://www.opticsplanet.com/truglo-trit-pro-walt-ccp-set-wht-tg231w3w.html
https://www.opticsplanet.com/truglo-tfx-walther-pps-m2-set-pro-orn-tg13wa3pc.html
Yes it should fit.
Yes, these will fit the PPQ M2 .45 as well.
Yes, it should fit.