An update. After months of living with my dead battery (iSclack would not work for me), I decided to use the provided suction cup, and surprise - it worked! LOL, so much for the iSclack tool! In any case, I followed the instructions and though it was a bit difficult (too small parts, too fat fingers, aging eyes), I was able to replace the battery. The battery removal was a bear, but with patience (and the use of an expired credit card as my lever), it did come out. Replacement of the adhesive strips was a puzzle - I eventually installed it "backwards" (removal hole in the tab on the left vs right) but this should not affect anything. Phone is charging now and preliminary testing of the home button/digitizer seem to be working. Once fully charged I'll do a full test on the phone to ensure I put things together correctly, but THANK YOU iFixIt for these instructions!
This is a Step 4 comment. I ordered the iSclack tool to help with my 5s battery replacement. After 30 minutes of trying to open the iPhone, I gave up and will try this later when I have a lot more time to spend on this. Before you ask, yes I did remove the two screws in Step 2. I must have a very tight fitting phone! Maybe next time I'll try a drop of oil on both suction cups to help with the adhesion. LOL, did not think I'd have trouble opening the case!