My D graduated from Bates last year and received the same scholarship to Whitman back in 2016. She ultimately decided against Whitman for a number of reasons. (As an aside, in her junior year, she studied abroad with several Whitties and loved them. She thinks she would have liked it, but doesn’t regret not going there.) D did not consider Colby as she felt the vibe wasn’t right for her.
Your comments about Bates–“Likes focus on community and impact. Seems more open to quirky kids. Doesn’t mind Lewiston. CS seems pretty limited. Film is combined with rhetoric”–are pretty accurate, though I believe Bates is expanding its CS offerings pretty quickly. D did a couple of film classes and rhetoric. She loved rhetoric and her favorite class ever was about analyzing Japanese monster movies.
Re Lewiston, has your S looked at this thread? The Horrible Misconception about Lewiston
Many students actually like Lewiston. 
My D came to love Lewiston, and I think it’s true for most Bates kids. Bates has a lively art scene and the Museum of Art has great exhibits.
One thing I love about Bates is that it prides itself on being inclusive. Any student can join any club, there has never been greek life, and it was founded by abolitionists.
Re the students, I would describe them as a big mix of kids from urban and rural places, friendly, outdoorsy, creative, cool or nerdy or both, liberal, and intelligent. They take their studies seriously, as do students at all the NESCAC’s. Professors have high expectations. The learning environment is collaborative rather than cutthroat. I also think Bates thesis requirement is a huge bonus. It’s something concrete which they can put on resumes as a big project which requires much work.
My D had a great experience and loved her profs and fellow students. You can read more here about why we felt a Bates education was right for her: How Bates prepared my student for her future - #3 by Lindagaf
Feel free to message me if you have further questions about Bates.