Project Beauty edits faces. Body mods replace bodies. There is no incompatibility issue between them because they don't modify the same thing, and it says as much on Project Beauty's Discussion page.
4. Will this work with body mods?
This will work with most body mods. This is because this is a face mod. It should work with Dimonized Type 3, Malos, Type V, etc. But it will not work with other face mods. For example, Josef Grey's makeup textures or Dimonized faces.
The mod will conflict with other mods that actually edit NPCs, and if you choose the HD version you will be installing unique textures that can be overwritten by other face texture replacers.
I use male and female body mods, but none of them "scream six" to me. Perhaps I'm just not looking hard enough?
I can recommend Breeze's Fallout 3 Male body mod- it has texture options, replacement meshes for the vanilla clothes and some DLC, and it comes in a scripted FOMOD for folks who don't like manually installing these things.