Think the Cake/Luka/Hayumi thing is a trap and misdirection (I am indeed aware how this might come across as)
And Cake does make more convoluted plays as scum so I wouldn't put it past her
Not familiarized with Luka's scumplay so there's a limited aka non-existent sample size there - but just by his reactions and comparing them to the last game we were in together, I'm willing to read him as town
I get Cake being scumread, I do
But the interference with actions can easily make 1) Cake LHF/more mistrusted than she already is 2) Luka perceived as a malevolent presence instead of a driving force for town 3) inducing paranoia around Hayumi because of her lack of activity
For 2, scum usually don't acknowledge their own missteps and attack back with circular logic. Even if I don't have any familiarity with Luka as scum, I don't sense janky motives on his part. He rides with it, he's more willing to interact. I don't think he's the type of scum to stick out or hide in the shadows, he's a bit of an in-betweener. But I don't see him taking a town leadership position and trying to be more proactive toward the later phases of the game.
As for Cake, it's easy to distrust her and become heavily suspicious of her play in general given her scum plays in general.
But I don't sense anything there that would make me confident to scumread her