I don’t get the question, possibly because the format of your post makes it difficult to read.
Will 5/3/1 make you strong as an ox, yes. In my experience (for what it’s worth) and observations on this site, the people who have the most success with it are the ones who fully understand the principles laid out in it and don’t dick about with it too much.
Pick a TM you think is lower than it should be. (You’ll see why as the weeks/months add up).
Don’t mess with the templates. This also applies to adding on extra stuff to make 531 “better”.
Measure your progress in months, not days or weeks.
Make sure your form is at least acceptable on the big lifts.
Buy/have access to: a weight vest, KBs, ab roller, band (for pull aparts). Of course, you’ll need a squat rack, dumb bells, etc… but those are a given.
Pretty much, yeah. There are people who seem to do well out of substitutions or changes that still sit in line with the principles of the program but for every Pwnisher who has success with these methods, there are 20 training newbies who complain it doesn’t work for them because it turns out they subbed half the exercises out and ignored half the advice.