We study Kerr frequency combs and dissipative Kerr solitons in silicon photonic crystal coupled-cavity waveguides (CCWs) with globally optimized dispersion at telecom wavelengths. The corresponding threshold for comb generation is found to explicitly depend on the main CCW figures of merit, namely, the mode volume, the normal-mode quality factor, and the slow-light group index. Our analysis is carried out by solving the nonlinear dynamics of the CCW Bloch modes in the presence of Kerr nonlinearity and two-photon absorption. Our results open the way to CCW comb generation via dispersion engineering and slow-light enhancement.