When reinstalling the home button, be careful you don't offset too much of the adhesive. This can result in a steeper edge when pressing the home button once everything is finished. Make sure that the adhesive closest in distance to the home button is as far from the opening as possible.
I had trouble opening the screen due to a warped suction cup that was bent up at one spot and also due to my cracked screen. My solution: used double sided tape between the suction cup and the glass. I had some command strips, but I think any double-sided tape could work.