Personally, I would go with Bowan. [name_m]Bohan[/name_m] autocorrects in my phone to Hoban 
bowen - familiar, straight forward pronunciation, aesthetically more pleasing (to me)
bohan - uncommon, will need guiding on spelling and pronunciation often, but better meaning
- since they’re not actually the same name, i recommend looking into the origins and meanings of each one to see if one speaks to you more.
- pronunciation of course depends on where you live, so that might not be an issue where you are
- since i see bohan is already another form of another name, perhaps it has different versions of itself as well
- do the starbucks name test! / similar people involved settings. give people the name both spoken and written and see how easy or hard it is, to understand the experience the kiddo might have