Should work just fine - materials will use unchecked PBR Mode, or even checked Legacy mode, where necessary so that you get the same look as in 1.4 or earlier. Then you can choose to manually enable PBR mode for any materials you want to use the new materials for, and tweak to get the results you want.
About the only thing I can think of that may be different is if you have hidden the lights in the viewport using the Command Panel display settings, then they will count as hidden lights and not render - simply check Render hidden lights in the Render overrides (Scene tab in the Render Setup) and they will render once more.