I'm pretty sure someone here posted about it, saying Robbie Daymond mentioned it at a con, but I don't feel like digging for it.
Eh, if the show was airing on TV and had specific deadlines, I could see that happening. But for a purely streaming/home video release, they can pretty much take as long as they need, so there's more time to iron out things like that. One of the big reasons they're redubbing this at all was to give it a consistent cast, in response to the original dub having a very inconsistent cast (to put it mildly). The original dub was under heavy time constraints to make broadcast deadlines, and had no choice but to recast if an actor had schedule or salary issues.
No, they can't possibly be. When a dubbing studio is hired, they are supposed to meet deadlines. If they told Viz "oh, we're too busy and so we decided to delay Sailor Moon" Viz would just get annoyed at their lack of professionalism and move their productions to another studio.