I agree with others who said 1) stinker races just happen sometimes, especially when it's over 60 degrees and humid, 2) the Pfitz plan is demanding, and its taper may not be steep enough, especially for a newer marathoner, but 3) it looks like your goals were appropriate and your training went really well.
I'd add that I myself don't like adding fast intervals only at the end of a marathon block as Pfitz does. That sort of thing affects different people differently, and you just have to experiment to find out what works for you and what doesn't. But maybe you're like me and that doesn't work for you. (I prefer to keep up some faster intervals throughout a marathon block).
Whether or not you could have salvaged this race by tapering more steeply or just differently, you had a really good training block and are going to continue improving once your body absorbs it. So I'd recommend backing off and letting yourself rest a little before jumping into another race or hard training block. My guess is that if you run mostly easy with lower mileage for a few weeks, then gradually reintroduce some quality, you'll be in PR shape by late Fall at whatever distances you choose to focus on next.
But there's resting up a little to absorb your training in the short term, and then there's the longer term, cumulative effect of repeated training cycles. Even though you had a stinker race, don't let that get you down too much because you did the work that over time is going to lead to better races even than you were hoping for in Erie. Keep your chin up and keep at it, just maybe tinkering with a few little things in your next full marathon training block.