is there a way when you create a unit it'll will be already selected?
I don't think so. You can make it where when it is created you look at it.
Commands atleast 1 (Unit) Move location 'view' on unit, Center view on 'view'
No, it isn't possible. It would make things a lot easier, though.
Try using the same unit but teleporting it different places, if that would work for your map, if not, I'm sorry.
If it's what I think you're asking for, it isn't possible, maybe through EUD actions, but those were disabled for 1.14.
Every time I hear EUD, I shudder. They're completely useless for the general mapmaker.
They are the only solution to this, though. So there is no practical solution.