Maybe we'll get an answer to where this fits on the timeline, but I'm suspecting we're not going to--maybe not in this season. I kinda feel like we'll get another Higurashi season to act as the answer arc of the series.
Hou is like supposed to be a complete collection fan disc of all the Higurashi sound novels from what I can gather. MangaGamer is supposed to be releasing all the titles on Steam over time, and "Festival Accompanying" was released just this May with "Dice-Killing" (which was apparently a fan disc that 07th Expansion decided to deem canon) being the next arc on the timeline. The last chapter on it is "Boisterous Gods" which I think is what you're talking about and I'm only just recently looking into it. It looks... painfully dumb, not going to lie.
Rika in episode two looked like a teenager, so I think the events of
Gou should canonically be after everything from
Hou. The more I look, though, the more I'm convinced the anime
is supposed to coincide with
Higurashi Mei, the gacha game, even the character designer was involved with it. And remember that the anime was originally supposed to come out in August.
Also, the meaning for "gou", 業, is "karma", or "result of one's karma; fate".
So yeah, watch this be a Bernkastel origin story, then.