I'm doing this for myself more than anything else. It will be released, but I don't give two shits if the FMA fan community accepts or rejects it. I just prefer subs to dubs, which is why I'd prefer to do this subbed.

The other problem is the differences in voices between the first FMA and Brotherhood - in Japanese, most of the actors are the same, but I know Mustang is different for one. When Funimation announced the English dub cast a few months ago, Alphonse's voice actor had reached puberty, so he's no longer playing Al - now it's a woman. (They said they're giving the former Al another part later, which I would assume is Ling.)

The difference in voices in the Japanese version isn't noticeable enough to be a problem IMO, but I don't know if Al's voice in the dub will be too different to ignore ...