Could this work in a layer cake?

Thank you all for your help! These are all great suggestions. ❤️

Another rumination regarding the strawberries. I'm assuming you would slice the berries you plan to put between your layers. I'd be sure to put those cut side down against the cake itself, and then slather on the chocolate filling. That way any juices the berries give up will be absorbed in the cake itself, and help anchor things together. Otherwise you could end up with some pockets of strawberry juice thinning out the filling.

Another idea (combine with Lori's about draining the yogurt more or do separately.
Don't stack your layers.
Rather frost the sides with whatever buttercream flavor you prefer, or leave naked.
Pipe a rim of whipped cream (rosettes, waves, whatever) around the top of each cake.
Fill in the center with the mousse.
Garnish (a few shavings of chocolate, berries, flowers).
Cut & serve.

I think it would depend on how much whey remained in the Greek yogurt. If you wanted to have a better chance of having it thick enough to stand up as a filling, I'd suggest draining the yogurt a second time, until it was closer to the consistency of semi-soft cream cheese. It would be less likely to squish out the sides that way I think. You might also be able to use it to frost the cake, at least on the top. With strawberries that ought to be just yummy.