It seems you've sorta covered gravity, in this thread, and along the way electromagnetism crept in, via your speculations on the charge of an EEP.

Let's see if you've actually covered electromagnetism, in a semi-classical way ...

What, in the ISU/EEP idea, is a photon?

How, in the ISU/EEP idea, does electromagnetism 'work'? As in, is it a force? (if so, how does it arise, what are its fundamental characteristics?) If not, what is it?

For gravity, what is its speed of propagation, in the ISU/EEP idea?

Which of the relevant equivalence principles, at the heart of GR, does the ISU/EEP idea say are wrong (or need re-stating)?

Going a bit further, perhaps beyond the scope of this thread, what are the weak and strong (nuclear) forces, in the ISU/EEP idea?

In particular, how many EEPs to a neutrino?