We report on new, to the best of our knowledge, techniques enabling both the mitigation of supermode laser noise and highly precise setting of the pulse repetition rate (PRR) in a soliton harmonically mode-locked (HML) fiber laser employing nonlinear polarization evolution (NPE). The principle of operation relies on resonant interaction between the soliton pulses and a narrowband continuous wave (CW) component cooperatively generated within the same laser cavity. In contrast to our recent findings [Opt. Lett.46, 5747 (2021)10.1364/OL.441630 and Opt. Lett.46, 5687 (2021)10.1364/OL.443042], the new methods are implemented through the specific adjustment of the HML laser cavity only and do not require the use of an external tunable CW laser source.