They had similar final years stats wise, but Lynch's numbers were a bit more impressive since that Cal team threw less than 2021 UNC. Also a RB catching 30+ balls and 300+ yards in college was more rare 15 years ago. So I'd agree with
@Ilov80sthat Lynch was a more proven receiver coming in.
I see the stylistic comp to Marshawn because he runs violent, but it really doesn't do Marshawn justice because he was so explosive along with being a tackle breaking machine. I think Marion Barber or David Montgomery are better comps. Although I think Montgomery was more patient than Williams, to a fault, so it's not as good a match stylistically. And Barber was bigger and more explosive/fast than Williams by testing numbers, so that might be a bit generous of a comp as well.