Opinions: are my children's (potential) names too similar?

Full disclosure I'm still at the expecting-to-expect stage, but definitely starting to think sibling names. I currently have a daughter called Erin.

If we have a girl, there's probably no issue, but if we have a boy, the only names that I really love are Owen and Aaron.

Are these names too similar to Erin? I'm asking for all accents and dialects here because in mine... (Southern English) they really don't sound too close. If so, are there any alternatives that anyone can think of?