You don't know who blocked or not, you are making shit up, stop talking like a positive affirmation...To be friend with someone doesn't mean you've to have them all around. Iris invited Erynn for reasons and took Alexis with them as a leaf. If you're with Alexis Iris says her she could invite MC but she didn't said that to Erynn because she knew about their history. Iris wants Erynn for herself.
If you say so. I think it's realistic.
Erynn wants you at the photoshoot but Iris don't want you at the beach where she's trying to hit on Erynn.
She didn't blocked anything. Iris does. She knows Erynn is MC's long time crush and could be a competitor. Why take the risk? Also in case Iris didn't, Erynn should have enough sensitiveness not to invite the ex of a fresh ended relationship.
Iris wasn't aware of long time crushes until, ironically, the beach scene(where she can notice something special), she only found out that the MC and Erynn know each other few days ago, seems like he never mentioned Erynn to her back in Alvarado... and in the scenes before the beach the words used suggested just friendship.
Btw upon learning this Iris takes super well this new "competition", she's very honest and friendly about it, pretty much backs away, definitely doesn't wanna fight with you over Erynn.
And if it's because of "recent-ex", it doesn't work with 2 conditions:
A-Erynn needs to be aware, there are many scenarios where you banged Alexis a couple of times, stopped and Erynn is totally oblivious to that...
B-A relationship needs to have existed in the first place, Alexis is skippable afterall.