Common Ion Effect explanations
Both your paragraphs are valid, as all present components are balanced by 3, mutually linked equilibrium reactions, with the respective equilibrium constants:
$\ce{HF + H2O &lt;=&gt; F- + H3O+}$, $K_\mathrm{a}$
$\ce{F- + H2O &lt;=&gt; HF + OH-}$, $K_\mathrm{b}$
$\ce{2 H2O &lt;=&gt; H2O+ + OH-}$, $K_\mathrm{w}$
with the relation $K_\mathrm{a} \cdot K_\mathrm{b} = K_\mathrm{w}$
$\mathrm{pH}= \mathrm{p}K_\mathrm{a} + \log{\frac{\ce{[F-]}}{\ce{[HF]}}}$