The host sends the current timestamp every 5 seconds to the clients. So if your clients are not in sync, they either have a serious problem with their clock chip, or your network lag is very high. Are you using a dedicated WiFi network?
Blank lines are rendered in the lyrics view. Please post an example.
Version 3.2 will have a Setting to use larger font sizes in the lyrics editor. That should help with placing the cursor. Did you know that Holding the Spacebar key will Switcher keyboard to a trackpad to position the cursor?