Not necessarily, those are the neutrals and but you need to have the incoming line power and not a light switch leg.
Like I said before, find where is your incoming power from the breaker panel.
As @JDRoberts said you need to nail down your use case first. Then we need to nail down what you actually have. It seems you have TWO switches on the stairs in a 3-way setup?
Take pictures of everything including the wiring into the boxes
I don’t think the set up is a three way, hence the OP’s desire to network the downstairs switch.
That’s pretty much correct. The top switch controls a couple of bulbs on the stairs just below, the other switch down there controls all the assorted bulbs and only has 2 worries going to a simple toggle…
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THere are 2 toggle on off old switches, one at top of stairs which is fine, the other downstairs which is annoying because if I forget to turn it off, I have to go down and do it. It is also inconveniently located to turn on or off.
While we’re getting the details, some photos showing the bulb locations with an indication of which switch controls which lights would also be helpful. 
With that kind of access. I would definitely replace the old 3 conductors with a new 4 conductors from the switch box to the gangbox so you have the option of putting in your smart switch. Don’t use dimmable with your setup as it’s not compatible with your bulbs/ballast.
