However if I'm looking for something or doing something in another split and I need to view a file or edit a file I don't go back to my vim split and open it there I just open vim right there where I am.
If I'm just editing two completely unrelated files I don't see any advantages to this workflow over opening multiple instances. Maybe if you have plugins that are slow to start up?
Regarding your second point, I behave similarly. If I am off in one of my non main editor tmux panes and I need to open a quick file, I will do it there instead of moving back to my main editor vim session. This is usually due to the file needing to be opened is outside the cwd of the main vim session.