Mips are per calculated per pixel. This will work just like any normal texture. The nearby texture will sample a different mip than the farther texture. It is still only one sample, because any given pixel only needs one of the mip levels.
Think about it in regards to what a single pixel must do. If you wanted two different mip levels to be shown for the same pixel, you would need to sample the texture twice. But if you want two different pixels to sample a texture with different mip levels, you only sample once and give each pixel a different bias.
I don’t know if you could duplicate the resource in memory by sampling it both in an array and out but I doubt it.
I can’t see why you would do that, but you could test it I guess.