So it occurred to me as I was rereading A Game of You over the long weekend, that we might have already seen Johanna Constantine replace Thessaly in Season 1.
So bear with me while I put myself at risk of looking like this guy:
So we know a few things already given the BTS tidbits we've gotten so far.
We know that Season 2 will be significantly compressing the storyline between Season of Mists and Brief Lives. (baring something incredibly surprising such as having filmed a LOT for this season during filming for Season 1 and also filming ahead for Season 3)
A Game of You has to be either cut or significantly shortened/overhauled at this point considering the BTS shots of Wanda's character and the above outline of episode names.
We know (due to @writing-for-life's excellent analysis) that the music themes for both Morpheus and Johanna blend together well.
So what struck me on this reread (and don't worry: I've got a draft started for my analysis) was just how much the interactions between Thessaly and Morpheus mirror the interactions between Johanna and Morpheus in S01E03.
First we get both women being generally unimpressed by Morpheus' ordering them about. With Johanna, it's in response to Morpheus turning up and demanding she take him to the sand.
With Thessaly, it's over him scolding her for acting rashly in taking the Moon Road to save Barbie.
This one felt more thematic to me than a direct comparison or direct quote.
Next, we get both of them lecturing Morpheus on his inaction where mortals are concerned.
(yes, I did learn how to make gifs just for this post: feel free to use) Johanna's lecture comes when Morpheus is ready to walk away after retrieving the sand...potentially leaving Rachel to her fate. Essentially blaming Johanna for leaving the sand there in the first place.
Thessaly's lecture comes as Morpheus is ready to walk away after removing the Skerry from the Dreaming. Although he hasn't stated his full intention yet, he's clear that he's not going to help them get home or get off the little bit of land that is left.
And finally, you see a bit of them both denying any interest.
(okay, so I made 2 gifs...) When Ric the Vic says that Morpheus is "not unfit", Johanna replies that he's not her man in a tone that makes it sound like she wouldn't consider it.
Meanwhile, Thessaly stews over Morpheus after he scolds her in the panels I posted above, saying that she's not buying his cool act and that he looks too skinny anyways.
So there you have it: scant evidence to be sure, but I found the 3 themes of each of them standing up to him for ordering her around, lecturing him in turn, and then also denying any attraction to be some fun parallels.
Given that we don't see much of Morpheus x Thessaly on-page, it feels like we have ample suggestions of Morpheus x Johanna in comparison. If they do go this direction, I really hope we see much more of it on screen than we did of Thessaly's blink-and-you-miss-it suggestion they were together.