Is the show very big? I wonder if it will go into a big musical house (similar size to the Imperial, Marquis, etc.) or try to go into a smaller venue (like the John Golden or Walter Kerr)"
That's a great question. No, I wouldn't describe the show as "very big". There are a few times where there are more than 5-7 people on stage at a time, but even those scenes aren't what I'd call "big" scenes. The dancing is pretty much limited to the steps of the Temptations during their numbers (and it's fantastic).
For the sake of the show, I truly hope they don't put it in a theater that has a capacity of more than 1200.
CZJ at opening night party for A Little Night Music, Dec 13, 2009.