It's possible that the display chip has some damage. You'd need to remove the EMI shields and clean the corrosion from there. If that does not work you could try reflowling the graphics chip. You'd need a hot air station ideally although a heat gun would work if you're careful.
I would suggest cleaning it until there is no stickiness. In order for the new adhesive to bond correctly with the frame/housing it will need to be completely clean. Once the new digitizer is seated use some heat around the edges to soften the adhesive then clamp it in place until it sets.