Given mostly for Hardy at Ep18, when Aya got kidnapped by Sirius, I would be 100% sure, that he would raid the place, where she's being held and murder Sirius or at least break his bones, once the barrier is deactivated
I also view Cal x Victoria into a problematic, but romance lover one (wish the Pyro Mountain Incident never happened), but at the other side a vengefully Blake x Victoria (by disguise himself as Cal; he also harbours some feelings for Victoria and is jealous of his little brother for that).
Protagonist x Taka: 100% a yes, because he deserves so much more and I'm willing to protect this precious boy.
Fern x Protagonist: Mostly like the Blake x Victoria. I could imagine, he had also feelings for the player, but seeing them with Taka, fills him with jealousy and goes full yandere...
Sirius x Lin: Their personalities find perfectly for each other. Two psychopaths with a desire of power and willing to kill anymore on their path. For Lin, she would be first a bit void of affection, but later gives in due for Sirius being the first person, who loves her. Imagining them as a Duo of Assassins.
Shelly x Noel: Same with Sirius x Lin. Just a cute ship with two children, who loves to read and have various knowledge about the most. Shelly would be the type to help Noel with his emotional problems and he in return to boost her self-esteem. Scale is between friendship and child romance.