Chosen Solution

Would it be possible to put the internals of the iphone 6 into the body of the 5s? Assuming you keep the screen and battery of the 5s, would the iPhone 6 chips recognize the screen / battery or is it a different physical connector between the two?

Lol good luck with that the logic board in the 6 is bigger that the 5s caseing plus connector would never fit Simple answer is no

They are different and will not function properly.