pukunui
Legend
They hadn't even figured out what Snoke looked like until a few months out from TFA's release, and Lucasfilm only recently said they'd finally figured out his backstory. So no, I don't think they had a proper outline for the whole trilogy. They might have had a rough, broad strokes idea, but I don't think they'd zoomed in on all the nitty-gritty details.You seriously don't think there was an outline of the trilogy nailed down before Ep 7 was even begun? Who Snoke is, who Rey's parents are, and what ultimately happens to Rey, Poe, and Finn as well as Han, Luke, and (subject to tragic change) Leia was all worked out ahead of time for the trilogy... it had to have been. This is Disney, they don't just wing it.
I agree, though, that Snoke may very well reappear in IX. I wouldn't be at all surprised if Phasma does too.