I rinse the bottles as soon as I pour out the beer. If they are not rinsed right away I don't even bother with them. If they are full of gunk, I am sure I will empty another one later.(of course with flip tops I might scrub them) Then I clean them using two 3 gallon buckets and Oxyclean...
Barkeeper's Friend is great stuff. It is by far the easiest and best way to clean a SS pot. Make the pot damp then throw the powdered stuff on there. Wait a bit then wipe it off. It will take practically anything right off with little actual work.
I did have to use some fresh yeast for bottling. I assumed the original yeast wouldn't be much help carbonating the beer, but yeah, same fermenter the beer went in after the boil for two years. The beer is actually pretty good.
It lasts a very long time. Especially if you mix it with distilled water and use it in a spray bottle. All yu really need to do is get the surface wet.
It depends on the tap water. When I mix it with my tap water it turns cloudy almost immediately.
"I have never had an infection" is not a good way to judge if your are doing things the right way. I use pH strips to test my StarSan periodically. If the pH is 3 or below it is still good...
Temp wise, styles have recommended drinking temperatures. I usually like beer a little warmer than fridge temp. Fridge temp is for horse piss beer which is nice once in a while during hot months.
Hoppier beers are usually best sooner. Hop aroma/flavor tends to fade. Sooner is whenever they...
$80-100 is a lot to spend on a pot. I bought this one a couple years back. Some people may tell you 8 gallons is a little small but it works fine for me. I use Fermcap and never boil over.
I get clear beer with just a primary. If you have gunk out of the primary you are probably not racking carefully enough.
Late extract addition may or may not effect you IBU's. It's debatable with plenty of anecdotal evidence on both sides.