My list is similar, but I'm a bit old school, so mine doesn't include any fancy temperature monitors or probes. I did finally break down & use an old made in the USA meat probe thermometer that I probably found at a garage sale or thrift store. Even then, I only really use that for a whole chicken or roast. I also use crumpled up newspapers instead of lighter cubes.
I would also add a CHEAP pair of tongs that you NEVER even have to bother cleaning, leave them outside, & just use them for picking up any coals that try sneaking away from you.
Also, if you can get a pair, the old wire baskets seem to let the ashes drop out more easily & are taller than the newer ones, so you can have the coals pretty much right under the grate. I'll make Marty's bigger better basket from the newer ones, but I'll also keep my wire sets because of the differences.
The baskets work fine. So far from what I can tell after using the SNS a couple of times the benefit is to keeping the coals o one side if you have a huge piece of brisket or other cut and you don't feel like rotating your grate when using the snake method.
The SnS is well built but I don't think think it's necessary unless you're really really looking for a new gadget to try out.
I'd rank these accessories as must haves over a SnS-
Dual probe remote thermometer. If you can get a Thermoworks smoke on clearance or open box for under $100 this is the one. If on a budget Maverick 732.
Charcoal baskets.
Javelin Pro instant read thermometer (as good as a Thermapen for half the money)
A good griddle pan cast iron or other.
Flip up grates.
Chimney.
Weber lighter cubes
Heavy duty spatula for smash burgers.
Good set of tongs.
Industrial size roll of tin foil.