I have been using 0.56.1 without any issues in MC18 so far. I add LAV Audio and LAV Video via the "Advanced - Custom" option rather than "Red October HQ" though, because I need to use LAV's DXVA2 Copy-Back in MC rather than CUVID, which it defaults to.
CUVID is the slowest hardware acceleration option for Nvidia, activates deinterlacing when it should not be, introduces artefacts due to decoding errors, wastes energy by forcing the card into its highest power state, and for me it is unstable when running inside MC - though it's fine in other players.
Anyway, if you are only using ROHQ, you don't have access to LAV's settings because they are auto-configured. If you add them via "Advanced - Custom" you can configure them via the DirectShow Filters menu.