Salinity would remain constant, as long as you don't add or remove water with a different amount of dissolved salt. If you put a kg of salt into a tank and it all dissolves, increasing or decreasing the temperature isn't going to make the salt come out of solution nor make more dissolve. You've added a kg and no more or less can dissolve than that.
Generally, temperature has little to do with the amount of dissolved ions in a solution, though granted temperature change is used to supersaturate a solution, but thats well beyond the scope of aquariums. Hope that helped and didn't confuse.
I believe that specific gravity does change with temp - based on my home distilling I know it affects the reading, so I think what happens is the reading will need to be adjusted for, just not the amount of salt in the tank lol. - could lead to problems
For my homebrew the sg comes with a table with a variety of temperatures.
The refractometer I have adjusts automatically to suit the temperature of the water to give an accurate reading.
Very usefull because I often make up my saltwater mixes in my garage which is cold and the water temperature is often about 50 - 55deg F whereas my tank is about 78... obviously I heat the water up before adding to tank but water temp does make a difference to a hydrometer's readings
That is my concern. My tank is 83F right now and I'm going to lower it to 68-70F before my octo takes it as a home, so my reading will change greatly. However, I know that salinity is a little low right now. 1.023, and I want it to be 1.026 when I add him. Will it rise with lower temperature, or would it go down?