KeterMalkuth

Generally speaking, any mod ought be able to be added to a world at any time without causing too severe of issues, so long as there's no preexisting conflicts between the mods you have installed, and the mod version matches the game version you're using. The only caveat I'll say is that any mod that affects world gen cannot retroactively affect already generated chunks. I can't recall of PS has any world gen components, but everything else should function fine. Obligatory I am not a lawyer mod author, this is not legal advice professional modding advice. I can't promise anything, but it should be fine.