Decompressed WoB Overworld Tiles

when it comes to using individual over world tiles do they need to be decompressed? for example, having the vector tiles which are exclusive in the WoB in the WoR while having kefka's tower and the cultist tower tiles in the wob while keeping all the other tiles unchanged.

If you want to edit the graphics, they need to be decompressed. You can decompress them with Peer Sprite Viewer then opening the exported binary file in YY-CHR to make your edits and finally recompressing the edited file in the ROM.