Toinv, some great questions you posted. You, like all of us, are anxiously awaiting clarification from Zenith on these many issues. I had some similar questions that I posted the other day here and here.
The only one of yours I can answer with certainty is that there are indeed two separate trials listed on ClinicalTrials.gov for ZEN-3694. The ZEN-3694 single agent trial (now complete) is listed separately from the ZEN-3694/enzalutamide combo trial (still ongoing).