[name]Do[/name] you think [name]Ian[/name] and [name]Ava[/name] are too close???
I do. Only because I had to pause between saying the names so that I would pronouce them properly. Since they both begin with a vowel (but a different vowel sound) my brain sorta freaked out. It wanted to say [name]Ian[/name] and [name]Iva[/name] or [name]Ava[/name] and Aan.
They don’t have the same sounds but they do make for a tongue twister. I probably wouldn’t do it.
[name]Ian[/name] and [name]Ava[/name] are definitely matchy, but no, I don’t think they’re overly matchy. The sounds are different enough although it is easy to get them mixed up.
I think its adorable, but it might be difficult if you ever have a third child to find a name that doesn’t make him/her feel left out 
They are similar but not to the point I wouldn’t use them together. As mentioned it would be difficult to include a third sibling later on with out them all sounding too matchy or one being left out. I’d tried thinking of some the I thought would go together with [name]Ian[/name] and [name]Ava[/name] but they all sounded a bit too close.
[name]Ian[/name], [name]Ava[/name], and [name]Ezra[/name] - too close
[name]Ian[/name], [name]Ava[/name], and [name]Elle[/name] - maybe
[name]Ian[/name], [name]Ava[/name], and [name]Owen[/name] - to close
[name]Ian[/name], [name]Ava[/name], and [name]Iris[/name] - maybe
Have you thought of a possible third to go with [name]Ian[/name] and [name]Ava[/name]? After this site I’m truly becoming a believer in picking names in sets of at least 3. I already have 2 so I missed the boat 