[name]Hi[/name], here are my thoughts on your names with my faves in bold.
[name]Arthur[/name] - I don’t mind [name]Arthur[/name] but it doesn’t “sound” very Welsh like the others on your list. [name]Arthur[/name] does seem like the odd one out next to your other favourite boys names, [name]Lennox[/name], [name]Harlan[/name] and [name]Rafferty[/name]. [name]Do[/name] you like Arthen/Arthian/Arthien, Arthfael/Arthmael or Arwel?
[name]Deri[/name] - It looks like a nickname or short form to my [name]North[/name] American eye = incomplete/lacks substance.
[b]Dyfed /b - It reminds me of [name]Dafydd[/name]. I quite like it. Comes in third.
Teifion (TAVE-ee-on) - My fave. This is lovely and I don’t think it would be bad paired with [name]Morgan[/name] if the pronunciation at the end is “on” instead of “an”. Three syllables is a definite plus. This is a winner.
[name]Tudor[/name] - This name is associated with [name]King[/name] [name]Henry[/name] VIII and his family for me so I don’t have good feelings about this name. I think I would pass as it’s too stuffy. [name]Do[/name] the Welsh spell it [name]Tewdwr[/name]?
[b][name]Rhodri[/name] /b nn [name]Roddy[/name] - My second fave from your list after Teifion. It’s a strong & masculine name.
My absolute favourite Welsh name for a boy is TALFRYN - I just love the way it looks and sounds! I also like [name]Iolo[/name], [name]Ifor[/name], [name]Geraint[/name], [name]Taliesin[/name] and [name]Brynmor[/name].
[name]Arthur[/name]- I like [name]Arthur[/name], and I [name]LOVE[/name] [name]Artie[/name]. It’s absolutely adorable.
[name]Deri[/name]- it does seem a little incomplete to me, but I like that it has personal significance. Maybe as a middle?
Dyfed- I like it a lot. I’d be concerned with pronunciation issues, but as you’re in [name]Wales[/name] I don’t think it’ll be much of an issue.
Teifion- [name]LOVE[/name] [name]LOVE[/name] [name]LOVE[/name]. It’s fantastic. It’s a different rhythm and number of syllables than [name]Morgan[/name] so I think it sounds fine. It reminds me of [name]Savion[/name] (as in [name]Savion[/name] [name]Glover[/name]). Also, I [name]LOVE[/name] it.
[name]Rhodri[/name]- Hm. The [name]Rod[/name] part makes it feel kind of middle-aged to me. It’s not bad, I just like your other options better, especially Teifion.