Morally its iffy who is worse, they both sleep around with people who are taken. Though Lena does more criminal acts that could be lawfully punished. Most importantly, stealing money. She couldn't get suit for animal abuse since she didn't really kicked it, the obtion text is exaggerating for the sake of humor (Kick the Dog trope).
Ian could get into trouble if his blackmailing would've been recorded, but he lucks out since Minerva wouldn't report him since it would put the heat on herself as well. Edit: And he is bullshitting, but I don't know how the law would handle it, it was still a ballsy move.