I have a P&S without a view finder and I hate it! Can't be used outside without difficulty. There is an optional add on viewfinder but its $130 extra. But I understand what you are saying about street photography.
I prefer and always use the LCD screen. This may be due to the fact that in the film era I shot mostly with medium format and some large format, which is composing on a ground glass screen. I find viewing on a flat screen more realistic as to what the final image might be.
Same thought here. Don't know about M, but my next camera will be a small one and with wifi capabilities. I want to control it from a smartphone. I'm looking for a Sony nex with wifi. Do you have wifi on M?