There are businesses out there that can replace the glass. They laser it off and I have heard with some of the machines you don’t have to dismantle the phone. I am not sure of the cost. Do a search around your location and see if there is a business offering this service.
I think you would find that the home button flex cable on the screen has been damaged when you removed or installed the screen. A tiny tear is all it takes. Sometimes I have to put them under a microscope to see the tear. You will need to replace the screen. Another home button from another IPhone 7 will not work. You would need to purchase a HX or JC universal home button if you go down this path.
You need to rule out parts first. Try another dock and if it still will not charge you will have to replace the Tristar IC. If you are getting into IPhone repair this is the most common problem you will encounter. Check out some YouTube videos so know what equipment you will require.
100% Isopropyl alcohol is perfectly fine to clean the connectors. Just make sure it has fully evaporated before connecting the connectors. When I cannot smell the alcohol anymore I know it is evaporated.
We always try and rule out parts first. So if you haven’t got the tools to diagnose the problem the cheapest option would be to replace the charge port and battery first, they only cost a few dollars. If the phone is still not charging you would move on to the charging IC’s
If the touch ID functions correctly I would be looking at the turtle IC. It might have got nudged during the transfer. You could try another screen but when there is a tear and or bad flex from the screen it usually disables the touch ID as well.
So you transferred the home button to the new screen and reassembled the phone and the home button and touch ID was working. Then you removed the screen again to replace the battery and now the home button is not functioning. There are two possible causes. · Check the home button connector is seated on the logic board correctly. · Check for a tear in the home button flex cable. (The one that goes from the screen to the logic board) You might need some magnification to detect it. This is the most common problem.