I’m not sure what to make of this, as you say updating TWRP worked, but the at the same time the version number doesn’t change (suggesting it didn’t work), yet you mention successfully flashing openGapps, which doesn’t work with 3.1.1 (suggesting the TWRP update did in fact work as you must be on a different version to not run into zip verification problems).
I can recommend this topic for more background on what people have done to get things working: