Agreed. If the lines/ pink mist show up the same on every app then either the LCD assembly is dying or the ribbon is getting disconnected. Most likely you will need to purchase a new screen and replace it. I'm sure ifixit has a walk-through on screen replacement

The circuit boards in this (and almost any other portable device) consists of surface mounted IC chips. As a general rule, it is impossible/impractical to actually swap ICs from one board to another as de-soldering and trying to re-solder these chips without crossing circuits is unhuman. In addition, the control board may not have the understanding to manage 64GB when it was designed to work with 8GB. Most portable devices must be repaired at the board level not the component level. (swap out the board with a same model motherboard from a unit with a broken screen from e-bay) I tried swapping just a surface mount switch and nearly failed with just two connections.

You could also use the device as a paperweight after taking it out of your current enclosure and re-purposing the enclosure with a new drive.

Any Sata solid state drive should work just fine in a Mac computer. The problem is that off the shelf drives would not be formatted to the Mac file system (Mac Journaled). Here is a good guide that should help you through the process: Apple Discussion

Nice work. I would recommend saying “popping” or “break free” about the tabs. I’ve done enough repairs to know that… a) they are too easy to break and … b) you don’t really mean “breaking” but breaking loose. Otherwise it sounds like this is an irreversible process.

Thank you for doing this. Keep it up