Not sure if the hop schedule fits the overall goal. I'm guessing that you are going for a smooth, slightly sweet, full mouthfeel. I would look at a small bittering addition with something clean and drop the rest of the hops. YMMV
Check with Denny but I don't think there are problems with not hitting a mash out. I suspect things will be smoother at about 170F but you will stop the enzymes anyway with the boil. It will take longer to boil if you sparge cool
Actually I liked it. Having said that I haven't brewed anything from it rather I used it to check my tweaks to my ipa recipe so this may not be the endorsement you're looking for. Some of the recipes aren't given in the usual format but if you're familiar with brewing you'll be fine.
There is quite a bit of historical stuff but to me (history teacher) that stuff is necessary to understand the style. There are also quite a few modern examples/recipes with some of the "why" explained.
I'm a batch sparger that uses bruunwater for both the mash and the sparge. Not sure if the pH is a big deal on the sparge but it is easy to do and some beers I want my sulfates or chlorides in a certain place. YMMV
Go ahead and warm it up and rouse the yeast. Not sure what ale yeast you pitched but I would imagine that 50 degrees caused it to floc out. I wouldn't be optimistic-except maybe about your sanitation but at this point what are you out?