1. The characters are being added one at a time. The next one is going to be Itsuki.
2. That has nothing to do with being an online game or not. That's because your phone is most likely not strong enough to run the game perfectly. Closing other apps on your phone can help with the RAM but it may still lag anyway.
3. the skip button takes some time to press to prevent players from accidentally skipping events.
4. This feels like you haven't update to the latest version because that bug should have been fixed with hotfixes we pushed out.
5. Yes, he's going to have more animations. He does have more with Itsuki too which will be released with the next update.