Welcome to R2R!
I'll chime in with my opinion on a few items on your list...keep in mind, just my opinion!!
Difficult to use, even for experienced hobbyists! A refractometer is the way to go. You can get a cheap one for under $30, or a Milwaukee Digital for about $100 (and that one is worth every penny)
My wife loves the purple color, but many consider this invasive. They will spread everywhere, just a heads up!
If you come from freshwater, you'll be used to vacuuming gravel. I personally do not touch mine, ever. Some do, but only vacuum about 1/4 of the bed every couple weeks or month, if that. The substrate in reef aquariums can, over time, develop a whole world of biology, so I just leave it be. Sometimes disturbing it can actually cause issues.