Those pre-made watercooling loops are usually more expensive and don't perform as well as a good air cooler. Just my opinion though.
No it's true. Brands like noctua have very well-performing air coolers, but they cost about the same as AIO water coolers so it's really a choice of preference
not really just an opinion, if you're not massively overclocking, water/mineral cooling is always overkill. it's just wasted money. if you want it for the looks, buy a couple cheap led's and stick them in it.
But a cpu cooler enables you to get a really nice overclock. I don't understand what point you're trying to make here, if you want to overclock your cpu then buying an aftermarket cpu cooler isn't wasted money
@OP your build is good, go for it. The only thing I would change is the case, I recommend the corsair 350D if you want to stay in uATX form factor. It has good airflow and great layout, probably better than the silverstone you have
Edit: Oh I see, you used someone else's buildlist. Like I said, change the case and you should be golden