I thought the Bethel Rd. trailer burned down. I know a trailer burned down but can't remember the details.
So if that was the case then Billy either went to Peterson or FWFs.
You mention questions about Billy being home all night.
So this brings up something interesting. It was said at Billy's bond hearing that Billy was staying the night on Peterson Rd, as opposed to staying that night with Fred which is where I think he was living.
It was said that Billy was not living with Jake and GW4.
So why would Billy just happen to stay on Peterson Rd. on the night of the murders?
Why not stay where he was living, with Fred? (My opinion he lived with Fred).
Why not leave Fred's, commit the murders, then go back to Freds?
Because he didn't want Fred or Robin to see he was gone. (If Robin lives there).
To have to get them both to lie for him was too complicated so he had to say he was staying on Peterson Rd which is circumstantial evidence.
So Billy was able to tell Fred he stayed all night over with Angie and that's why Fred told the press:
"None of us was anywhere near that place that night."
Billy couldn't count on Fred and maybe Robin to be his alibi, which is what they would be if they said he was sleeping in his old bedroom at FWFs all night.
But very interesting that he did seem to count on her to lie to the GJ for him, why else was she looking up the night before her GJ testimony how to lie to a GJ? Plus Billy was living with her at that time and likely was involved with her search, or he himself did the searching.
2 cents only