a bunch of people seem to be missing how electronics work. While the signal may not pass in one end and out of the other of these resistors, the music signal -- subsequently amplified -- voltage is sensed (dropped) across them. Any nonlinearity or noise will be amplified. They are in fact very, very critical.
That said, most resistors are excellent . Buy 1% metal film. I have seen extensive listening tests of various compositions and brands, and at the end of the day its a bunch of trade-offs. So my "best" might not be your "best".
The Dale RN55 and RN60s are mil spec and excellent; a step up are Vishay branded and above that Caddock bulk metal.
I frankly use respect names tat in wholesale i get for /10-1/20th the cost of even the Dales. That said, the first stages of MC are the one place i might just pry my wallet open and spend a but more. The most critical number are TC and Noise.
I have built nearly a dozen variations of prototypes MC RIAA stages over the past 2.5 years and the design has always been vastly more impactful than brand X vs brand Y of resistor.
G