I hate to be one to break everything, but I have a slightly different theory. Neo's voice being identical to Mwu's could also be one big coincidence.

In the last two years or so, watching different series (in Japanese w/subtitles), I have heard this guy's voice (Koyasu Takehito) everywhere. Obviously as Neo in SEED Destiny and Mwu in SEED, but also as Kakei Jubei in Get Backers, Balladbird Lee in Gungrave, and that blonde Valentine Brother in Hellsing. Everything he's been in (aside from Destiny, since it isn't too recent) can be found here.

Anyways, he must be a very popular voice actor in Japan at the moment, so it seems like he's being hired to do prelay work for nearly every new anime series.