As a reader, I would find the James / Jake thing confusing. Some others have said they would too, and some others have said they wouldn't. So it's hit or miss, and your choice.
To me, those names are both common enough that it would be easy to find a replacement for one. They're not special, they're not part of character development or world building - just every day names.
I do understand a fondness for names, and an attachment to certain ones ... we start thinking of characters as those names/people, and changing might be jarring - but I've known people in Real Life who've suddenly changed their first names, and after awhile the new one just becomes natural to them.
To me, those names are both common enough that it would be easy to find a replacement for one. They're not special, they're not part of character development or world building - just every day names.
I do understand a fondness for names, and an attachment to certain ones ... we start thinking of characters as those names/people, and changing might be jarring - but I've known people in Real Life who've suddenly changed their first names, and after awhile the new one just becomes natural to them.