This is where I get most of my suits.
Kostymer - se alla designerkostymer online på Tiger of Sweden
They're only $600-700 a pop and easily look like they could be priced in the $1500-2000 range. Similar in quality to something made by maybe like Paul Smith or another designer at that level.
For shoes, I always get rubber soles. Like most Manhattanites, I walk a lot and they really are just that much more comfortable. Always Prada since 2001. These are boots but here's an example of the typical sole.
Prada Rubber-Sole Chelsea Boot, Black
I never bother to get them resoled because I've heard that it's difficult to find a cobbler who can resole them properly with the red stripe. Oh well. I've gotten much better about wearing them less often than I did from 2001-2010 when I wore them pretty much every day. So now at least they last longer than they did back then.
As far as your questions about the fashion rules for leather sole protectors or poly blend suits or whatever, I really have no clue. Seems like some stupid shit to be worrying about. I prefer to just buy nice things from brands I trust because I really can't be bothered to spend time thinking about such nonsense.
Have luck!