Yes, Caleb lied and spied on Hanna but he's the only love interest who didn't intentionally torture the girls psychologically. I say intentional, because he probably did mess with Hanna a bit when she thought she was getting the jewelry but found Jenna with it instead. But Ali, Toby and Ezra were seriously mind fucking, not just their love interest, but all the girls.
The writing on the show is weak in many ways but the characters are really lacking. I would say Hanna is the most fully fleshed out characters. You know her personality and her motivation. And she has the best relationships with all the other characters. I wouldn't say she's the most forgiving, but like you said, she has a big heart which makes it easier to create and explore relationships with the other characters. I think the only person she holds a grudge against is her dad and his new family but luckily they dropped that storyline. But then again they throw in random tidbits like her not know the name of the SATs but scoring really high on the test. It's very contrived.
Emily and Spencer are good characters, but not great. Emily kind of has two personalities. Sometimes she's kind and sweet and forgiving but then something happens and she turns into a vengeful super sleuth. Spencer is great but she's more of a trope than a character. Both girls seem to have conflicting dual personalities. Whenever the show needs to introduce a new secret, it's like they backtrack the character development. Spencer's drug abuse pretty much came out of nowhere as did her kinda fake/kinda real mental breakdown. And I won't even get into Aria. She's just a sidekick masquerading as a main character, but maybe that's what happens when the villains outnumber the heroes on the show.