DLC Creatures in Commonwealth?

[ChorbyPorkins]

I haven't modded before, but I was wondering how one might go about adding some of the creatures from the DLC content to the Commonwealth? I dunno if it's possible to pick and choose, but I'd love to see Gulpers and Fog Crawlers around the water (I know with at least Fog Crawlers that's lore breaking, but they're unique and interesting), as well as things like the Cave Crickets, Bloodworms, and Rad Rats as well (those shouldn't really be lore-breaking, I see no reason they couldn't be found elsewhere?). I'm sure I'm forgetting some other (I intentionally did not mention Anglers, not sure if they could work outside of Far Harbor).