Are IQ-samples independent from the carrier frequency?
I'm not sure I understand your question, but here are some thoughts.

Say you have a passband (that is, with a carrier) quadrature signal: $$s(t) = x(t)\cos(2\pi f_c t) + y(t)\sin(2\pi f_c t).$$ Here $x(t)$ and $y(t)$ have bandwidth $B&lt;&lt;f_c$. If you sample this signal, the specific samples you get will obviously depend on $f_c$.

One almost never does that; for many reasons, it's better to remove the carrier. So, you can obtain the low-pass equivalent (complex envelope) signal $$s_{BB}(t) = x(t) + j y(t),$$ and sample that instead. Then, the samples will not depend on $f_c$.