Nope, why it should be like that? Your soldier with his presence nullifies existence of an enemy that is about to go this way? It is indicator that there are enemies. If you don’t want enemy poping near you just stay away from that spawning point or if you can’t stay away use overwatch.
Nope. This is not a StarCraft. How does it matter how many HP soldier has? Something grabs him and infects instantly. Marines in Aliens movies had some advantage of being less tires or hurt when facing face huggers?
Why the turret should weight more? This is not an anti-tank cannon, but drone rifle. It has weight of Machine Gun - it is enough.
So equip them like that!
Nothing stops you from flying like you wish. But if squad needs to be sent in fast manner elsewhere without returning to base then game allows that. And what if the mission is to find resources in couple of places? Mind blown? 