If you are doing a retro pixel art game, you will likely want pixel rounding turned on. This will make sure that all pixels are drawn at screen pixels and there are no non whole number positions which can deform your pixel art.
Using lerp to create a smooth camera is a fairly standard across most games.
You don't need to use a second sprite for your camera either you can use the system action "set scroll" and use:
lerp(scrollx,target.X,1-f^dt)
lerp(scrolly,target.Y,1-f^dt)