I find that generally when I look at gear lists, I find things that are missing, IF I'm looking at them for completeness (I generally don't: it's a fair bit of effort).

You might want to look at several other packing lists (there are many public lists to be found) and then decide from those if your list is really "complete".

You list 12 items. I typically have 100 or so --- admittedly not everyone lists things to the same level of granularity. So for example, in my list I have toothbrush and tooth powder as one item, but floss as a separate item (it's also repair gear, along with a needle, which is a separate item for me). Certainly no single "right" way to do this.

I suggest that you pack up and go on an actual trip, short or long, and then you'll find out for sure what your real packing list includes. The "stand on bathroom scale with and without pack" is a fine approach if you don't want to geek out with spreadsheet and weigh individual items to the gram.

What I use for trips that I lead is a simple spring scale --- these aren't expensive. The most accurate reading (i.e., what people are really carrying) is made at the trailhead.