Do you pronounce Cathan the Irish way (Kane, or Ka-han) or phonetically, like "cath-ann?" Is Chael another Irish name, pronounced Kyle (kinda like the last half of Michael?). Just curious if you want another cool Irish name.
If you're going Irish, then I think Kyan is the only option there. However, it's *really* similar to Cathan-- probably too similar to use.
Cody & Jaxon are very trendy faux-cowboy names.
Jaron is interesting; it's a variation of Aaron. Of your selections, it seems like the most viable.
Bottom line: I would definitely not use another "2-syllable ends with N" name, especially not one that starts with a C/K sound. You'll mix up your boys.