M.M.
At 4 mos, she has become aware of her surroundings. She knows when you're there, and she knows that if she calls, you will come. She likes you, and wants to hang out with. Even overnight!
Since you're against any kind of CIO, all I can tell you is to be careful with how you respond, unless you don't mind tending to her all night every night.
You have reached the stage of her development when a habit will form, unless you begin some sort of sleep training.
There are no-cry options. I would suggest getting a book and learning those techniques.
This change in pattern is 100% normal for her age and development stage.
It will continue as she grows and reaches new milestones.