FWIW, it's not a given that Project Nemesis / Bellerophon is the same artist are SAJ. In their blog, SAJ refers to PN/PB always in the third person, and claims to be learning 3D modelling (esp. in the first posts).
PN/PB has released all of the assets used for STFW to the public, so anyone can pick them up and start a series on them.
It's quite possible SAJ just picked those up and went along with the theme (and with the openness in sharing the assets they have developed for the Lithium and OHB series).
The same goes for Tira Yugen and The Rather Magnificent Family Bubble. TY refers to SAJ as their mentor, and has explicitly said she's using the models SAJ has released to the public. (And yes, RMFB is “officially” set in the STFW universe, we see this in the recently released Chapter 4: Anna's ex-boyfriend Patrick is Bob's psychologist from OHB1).
While it's definitely possible that they are all different pen names with the same person behind them, personally I prefer to keep each comic/series associated with the corresponding pen name (if not else, to respect the author's wish to keep the “writing persona” separate, if it's all by the same author). I don't mind the complete STFW series being in this set, but I think it would be better to name it properly ;-)
If we throw RMFB in the set we can just rename the thread to something like “STFW Universe Collection” with all the author names tagged.