@aniko Benson is a rarely heard name, so I like it based on its more unique quality. When it comes to Cambell, I hesitate to advise changing the common spellings of names, because it sets the kiddo up for having to spell their name out for EVERYONE for every school, work, and official filing thing (doc offices, driver's license, etc.). It becomes annoying. I have a name like that, and my spelling, while less common, isn't even rare. But i have to ensure i spell it out Every. Single. Time. regardless. It just gets them stuck into the category of people who can either never have anyone spell their name correctly, even family, or have people struggle to pronounce it correctly (though the latter wouldn't likely be an issue for your son). It's a personal choice, but if you're going to "overthink" it, I'll throw that out there.
Like you, our oldest's name was an instant, hard YES! When my middle was on the way, we agonized over names and ended up picking two (one dad really liked and preferred, and one I really liked and preferred) so we could make the final decision when we saw him in person. We ended up going with the name i liked more, because it suited him best. Middle names are either copies of family members we wanted to honor, or close interpretations (like middle's middle name is Harrison instead of Harold), so that part was easy.
Girl names were hardest for us. So when our youngest was born, we had 4 names we liked, but none that really stood out to us. Once she arrived, we knew EXACTLY which one she was, and we grew to absolutely love her name. As a bonus, every woman over the age of 50 adores her name, as it's the name of one of the golden girls (real name, not character name).
In short, I'm on team Benson, but for the sake of making things easier, why not pick two or three favorites, and see what speaks to you once you meet him?