I don't think Bella is getting out of character. It always remains The Ice Queen, but has always had a soft spot for MC, it is no coincidence that she immediately hosted us at home, she has always been open with us, until we find out more about her past it is difficult to understand why, but to made Bella is consistent with herself, she is attracted to us and comes to meet us in small steps.
On the other girls, my favorite from the start is Jill, but honestly the more I have moved on with the story the more I have lost interest, it premises that after the last chapter I have a theory about whether she is related to the MC and maybe she is this is holding me back, I don't like incest, so I hope that the next chapter will remove this idea of mine.
In the last few chapters I've liked Quinn instead, I'd say she's my favorite now, I love bad girls, my fault.
Maya, she never attracted me, Josie is beautiful, she has a perfect body, but I can't get beyond hers, as long as I can have a good time with her, that's fine, but I don't think it will ever be my final choice.
Sage, I love redheads and Sage also has a perfect body, in the last chapter a new side came out, more sensitive and above all more intelligent than I thought. She begins to interest me.