mod + vanilla

Hi! Hoping someone can help me figure out which mod is causing this issue in game. When going into Willy's shop, he does not sell any of the vanilla items, only modded ones. He doesn't sell the fish smoker recipe, any fishing rods (I'm fishing level 6), bait, bobbers, or fish. I have...

I've seen people solving the modded + vanilla co-op saying that just getting rid of space core is enough, but I got a new computer and never added the space core files. My partner doesn't want to have to download smapi just so we can play. Do I need to download the json assets or something...