Getting off topic, but they definitely are. Part of their whole story is that they were in a relationship, but just too afraid to admit it. Do a path where you break them up and it becomes very, very obvious that it wasn't just casual between them.
P.S. The person you were responding to (608xperience) is involved with Bare Witness development. I'd take their word on it.
To be fair to ashcatch, that still technically means they aren't in a relationship. Personally, I don't see how that makes it any better for the MC to swoop in on one or both of them, but then again I didn't particularly mind when the MC and Hannah considered opening their existing relationship, either. If someone
really dislikes the thought of someone coming across as the third wheel in a poly relationship, I suppose can see why they might consider the
Bare Witness setup superior: all three of them were together for the moment of transition where it became something more than a fling.
(Presumably someone who felt that way would not continue on for the full SMASH ending.)
It's open to interpretation what this means. Maybe Alorine is back to evil plotting. Maybe she's turned over a new leaf with Alora and felt like doing something nice to repay you for not killer her by being there to help officiate in the only way she can. Maybe she knows something about MC's future potential bloodline. Etc.
That's putting it mildly. It's open to the wildest of conjectures because we have literally no information to help guide our speculation. Even the fact that it's related to Alora/Alorine has to be metagamed from seeing the two endings side by side.
No theory can be falsified. That's not the best way to weave an ambiguous ending, IMHO.