I'm guessing the "That never happens" was in response to the first part of the post about hoping the refurb finished early. I wouldn't say never, but an early finish to a refurb is uncommon, and the more unlikely the shorter the refurb period.
I think the poster meant that if Disney says it's down for a short refurb through the 19th then it won't open before the 19th. I was confused at first too because I've ridden during the fireworks a ton of times too. I agree. Short refurbs are very unlikely to open even a day early. Longer refurbs will sometimes have soft openings a day or so early.
Noooooo! Our last trip was 4 years ago when it was down for a total overhaul. I was so excited to finally ride it, but we'll be there the 18th and 19th. Grrrrr!!