Configuring the Dock to be Spaces-centric
3 questions in one, so I numbered your points to make answering easier…


Set the app's space compliance to None [right click the app in the Dock]





1) Mac apps don't do that, no new instance will be created unless none exists.
2) Can only be done if the compliance is set to All Desktops - but that means it will always follow you around; probably not what you want.
Focus will switch to that app, whatever Space it is running in. There is no way to change that behaviour.


Pro Tips…

Click/hold the title bar of any app &amp; use a key command to switch Space
 - by default  Ctrl ⌃   num  will bring the app with you to that requested Space

Personally, I find separate Spaces per display untenable, so have it switched off. My monitors switch in pairs…