So the timeline as far as I can figure goes like this (I'll mark the confusing/inconsistent parts with a
*):
Monday(?) night: Chloe overhears Rhoda and Jared doing... something. Talking? Having sex? It's not entirely clear. But she hears something that makes her suspect Rhoda/Jared are related.
Tuesday: Chloe subtly manipulates Rhoda into checking on MC/Izzy at the hot springs.
Chloe/Claire/Kathy see the Rhoda/Jared/Rose/MC/Izzy talk happening, and it's revealed that Chloe was purposely trying to have Rhoda (or Jared) see MC/Izzy at the hot springs because of what she heard earlier.
Rhoda/Jared/Rose tell MC that they know about him and Izzy, and that they're okay with it, but not why they're okay with it.
* Later after the badminton game, Rhoda asks the girls "How many of you are in love with your father?" and the scene ends. Do the girls just avoid answering or straight up lie? Because if they told the truth here, the next part doesn't really make sense.
* Friday: Rhoda overhears Kathy/Claire/Chloe's banana handjob/blowjob lesson, and brings back a dildo for them to practice with. Kathy asks her "How long you been there?" and she responds with "Long enough to confirm my suspicions about you and your father." Which seems strange for her to say since she directly asked them about their feelings on Tuesday. So again, did they avoid the question/lie earlier? If so, why end the scene there instead of (for example) having the girls come up with some classic laughably bad excuses ("Gotta go walk my goldfish", etc.) and run out of the room?
* Same scene, later on. Rhoda learns about the letter from Michelle and guesses that she knew about her and Jared. The girls hear her thinking out loud and ask her about it, and Rhoda says
Can you all keep a secret? Even from Isabel and your father? At least for a short time.
...
Given what you just told me, I suspect your mother knew. And apparently was fine with it.
Like her, Jared and I have no issues with your father and Isabel, and I suppose with all of you, if it comes to happen.
It seems your father may end up with quite the little harem. But as long as you're all happy, who are we to judge?
Anyhow, as I was about to tell you...
She can only really be telling them that she and Jared are siblings, and the fade to black and "A while later" is presumably so that the player can still be surprised by the official reveal. But if she did tell them, then the next bit doesn't really fit, either.
* Sunday: Rhoda and Jared finally reveal that they're siblings. Chloe says "See? I told you", followed by Kathy "Yeah, you did." and Claire "Uh-huh." Which doesn't make sense if Rhoda directly told them on Friday.