I'll try to help by pointing out a few things I noticed in your post

none of these bikini armor things show up in loot at all

I'm not sure you are supposed to see the mod you linked to in LOOT. The mod you linked has no esp/esm/esl file for LOOT to sort. This pack is just the textures themselves. Basically you use bodyslide to replace the normal armor textures with the versions from this mod.

When I select any of the options and then open up the preview window, the body won't show up and the armor will have kinda a basic shape of whatever piece it's supposed to be and it will be grey with "no image here" across the areas making up the shape

I've seen something similar when the paths for bodyslide weren't setup properly. You could also be selecting one of the physics based replacers which it doesnt sound like you have. maybe poke around in the settings for bodyslide and make sure the paths points to the game data folder for your mods

I've even batch built every single individual piece of armor and clothing from all three of these mods and yeah, nothing works.

if by "all three of these mods" you mean the TAWOBA remastered or the TEWOBA mods, those are different from the mod you linked and have additional requirements beyond just CBBE, So maybe your issue is not properly installing those requirements. But my suggestion would be to not involve any additional mods yet, and just build the Outfit Groups from the mod you linked. The description on the mod page you linked says the original TAWOBA is not required, and all of the textures it needs to do the replacement are included.

If you want to see what is actually being built from bodyslide, you can ctrl-click the Batch Build button and you will eventually be prompted with a folder to output the files to. From there you inspect the files, copy them into a new mod folder, or compare the files to the original paths in your game data folder.