[name]Jax[/name]- I’m not a fan. I prefer [name]Jasper[/name] or [name]Jackson[/name].
[name]Leo[/name]- I love [name]Leo[/name]! If the twin ‘o’ endings really don’t work with each other, I’d suggest trying to find a longer form of the name that [name]Leo[/name] can be a nn for like [name]Leonard[/name] (I also thought of [name]Leonardo[/name] but that ends in ‘o’ too!!)
[name]Rio[/name]- a really cool name but again, the ‘o’ ending of your last name as well might disrupt the flow quite a bit.
[name]Milo[/name]- ditto to [name]Rio[/name]
[name]Matteo[/name]- I love [name]Matteo[/name], also spelled with 1 t (which is how I personally prefer it.) If you like the nn [name]Matt[/name], you might be able to look over the ‘o’ ending with more ease.
My favorite is [name]Leo[/name], followed by [name]Mat/nameeo! Good luck!