Thanks for the tip, I had the same issue with the suction cup not working on the cracked screen. Applying clear packaging tape over the screen helped but it still didn't come apart. Ended up using a blow dryer on the highest setting to help melt the adhesive around the bottom of the phone (being careful to not let it heat up too long) which eventually made it possible to wedge the spudge inside.
The guide and photos were great along with the replacement part from iFixit. Probably the easiest screen replacement I've done so far.