This whole lipsync thing used to happen in Deresute too back when it was released in Onegai! Cinderella's solos. You choose a girl who had a solo version and even though the song was sung by her, the rest was also lip syncing along with her. This was fixed in an update however, so we can only hope that the same goes for Millitheater and Livesute.
Also, some of them (at least in Deresute and Millitheater, didn't really checked the Livesute PVs in detail to notice this) sing when being back dancers in the chorus parts, maybe because Scamco wants to give the feel of having the backdancers be the ones who do the chorus parts. Again, I didn't check the PVs in detail (too busy looking at Michio and Shiro ww) but I doubt they would make the backdancers lipsync the entire song.
The choreographies are AMAZING, and compared to the first PV where they danced like robots, they really smoothed them.
Now, the actual problems here (imo):
-No hair physics? I mean, I know the game is still being developed and they need to polish a lot of things, and they probably rendered the MVs without paying too much attention... but did they really need to use models like Chris', one of the few idols who have long hair? That makes that even more notorious! Chris' hair stays rigid the whole song. It looks like it was made out of cardboard. Again, I'm sure the models are still not finished and they need to add physics to some of them. Or at least, that's what I want to believe, because I doubt they're gonna leave long haired idols without physics when some short haired models like Kanon's and Jiro's have physics (even though they look so bad... hope they also fix this).
-Weird proportions... this can be noticed in SEM's PV the most... it may be only me, but, don't they have really long arms and legs compared to the torso? Mofumofuen's models look nice, but SEM's models look so out of proportion. Again, this may be me, so if someone can confirm this...
Overall, the game is looking amazing and I can't wait for its release! They really need to polish those things asap tho, because considering how they already opened preregistrations and seeing how Scamco always release their phone games two months (more or less) after this, the game may be released in September. And considering how the anime airs in October, the release date may be at the end of September, so the game can promote the anime and viceversa. It's a win win.