One last question: If I edit my world with mods, (Using WorldEdit to transfer my structures), will it still carry over to vanilla minecraft? Or will I always have to open it with mods?
Like Sidmarill said, if your structure already has mods in it it will remove the mods. But as seeing you are in vanilla, you could use the worldedit mod to make changes and than change it back to vanilla, it will warn you if you leave a modded block it's missing these and make a backup of it, but backups are always a good thing in the first place. And even though you are probably in 1.12.2 the mod for 1.12.1 should still work. Hope it all helps.