I carbonate every batch at 76 for 3 weeks then I store at my basement temps which are in the low 60s. I have goofed and had a batch get above 90 for a couple of days during carbonation (actually won a medal for that beer).
Carbonation temps don't have the same effect on your beer that high fermentation temps do.
Secondary fermenters are rarely necessary. Unless you are transferring onto fruit or bulk aging for an extended period of time there is no need to transfer to a secondary. This is a process that has hung on with some brewers who have been brewing for a lot of years. It used to be that it was necessary to get the beer off of the yeast but isn't any longer.
Just wanted to give an update on my Long Play IPA. Tonight I finished cold crash and bottled it for a conditioning nap. First, I took out a little glass of it to see what it tasted like at this phase. I have to say that I was relieved and very impressed. Since I fermented it without the cooler, I was worried about it having the apple cider taste. It was awesome! Not very hoppy, but definitely an IPA. Tilting the keg and doing the cold crash was a good move. The last bottle did get some trub, but I marked it as a tester like someone else recommended. I was curious to see how Werwer2018 made out with his beer.