2)Maybe he had an hiding place but I think that after all this years he grew confident and he could let some pur momentos in his house and went unnoticed.

3)the map you mention was recovered near the crime scene during the investigation of the 42 nd attack (December 9, 1978) of the EAR, it's unknows if came from the EAR... You can read it on Wikipedia( Golden state killer page)

5)According to friends and family the EAR/ONS was brought into discussion just one time , but a the moment nobody knows. In my opinion JJD kept his " second life" all to himself. The matter if he had or not an accomplice wa rised at the time. That came from survivors's allegation , according to they heard two distinct voices. On tv I heard some JJD's acquaintances saying that when JJD's had outburst of anger he would engage in conversation with himself. In another occasion as mentioned in the book" The Visalia Ransacker" when the burglar was confronted by Officer MCGowen ,before the officer before being shot, heard the Ransacker saying "oh my god don't shoot me!" in a high pitched voice almost feminine. So if you combined the two episodes it could be possible that the voices heard came from one offender.