[name]Oren[/name]: Because I think of conservative [name]Oren[/name] Hatch, I can’t see [name]Oren[/name] with the free and spiritual [name]Bodhi[/name] and [name]Ryo[/name].
[name]Ren[/name] (love it, but we have [name]Ryo[/name] already): I have to admit that even though I never watched the show, I think of [name]Ren[/name] and Stimpy.
Rei (same): I think this is nice, but like you said, it’s another R name. Aside from the i ending, I don’t think it sounds matchy with [name]Bodhi[/name], because they have different ending sounds.
[name]Kai[/name]: I can definitely see [name]Kai[/name] with [name]Bodhi[/name]. Yes, they look matchy because of the i endings, but they don’t have the same sounds.
Simja/[name]Simcha[/name]: I’d personally go with Simja over [name]Simcha[/name], because depending on where you live, I think you’ll encounter pronunciation issues with the Hebrew [name]Simcha[/name]. (I’m guessing people will mispronounce the “ch” sound has a “ch” sound or a hard c sound, when it’s neither. ) I can also better see some of the other names with [name]Ryo[/name].
[name]Chaim[/name]/Chai (I actually don’t mind any tea connections…weird): Like [name]Simcha[/name], I think [name]Chaim[/name] will encounter pronunciation issues with those who don’t know how to pronounce its beginning sound. (I also can’t see [name]Chaim[/name] and [name]Ryo[/name] as brothers.) Because of the tea issue, I personally prefer [name]Kai[/name] to Chai.
[name]Dan[/name]: I think of [name]Dan[/name] as a nickname for [name]Daniel[/name], but I think it’s handsome. (I can better see something more exotic with [name]Bodhi[/name] and [name]Ryo[/name], though.)
[name]Dai[/name]: If I’m pronouncing it correctly (with a long I sound, like eye), [name]Dai[/name] sounds like the word “die,” so I prefer some of the others.
[name]Ben[/name]: I love [name]Ben[/name], but I think of it as a nickname for [name]Benjamin[/name] or [name]Bennett[/name], neither of which I can really see with [name]Ryo[/name].
[name]Ira[/name] (the other half thinks Irish Republican [name]Army[/name]): I think it’s a great name, but I can better see [name]Ira[/name] with vinatage or clunky names than I can with [name]Ryo[/name] or [name]Bodhi[/name].
From your list, [name]Kai[/name] is my favorite with [name]Ryo[/name]
Good luck!