I think they are fine! I think a lot of people do that anyway - tend to choose names that have the same flow or similar sounds because that's what you like! I always seem to like names that end in the "ee" sound whether it be spelt ie, ee, ey etc.
I think it's fine!
My brothers name is Nathan, and mine is Teagan... so we both have the an going on... I've never really thought of it as being weird!
My cousins name is Lachlan too, so I love it hehe
Bookmarks