Chosen Solution

If I replace only a motherboard from someone’s used iPhone Will I be able to use my iPhone 6 Because I saw online that Touch ID thing is connected with the ic chip

Ok, so you can do it. You’re correct the home button is married to the logic board. So you can transfer the logic board and home button. I mean…like..it just doesn’t make sense why you would want to. The only thing I could think of..is…you want the good uncracked display on the other phone? You could way more easily transfer that to the one with the logic board you do want, with the home button