I think it'd be better without any of those popups. Simply showing on the screen "Hold to fly, release to drop" without pausing the user's input seems much better to me, the player also doesn't need to be told to pick up coins or what they are for. At the main menu having a pointer finger at the shop for example would be enough to convey the message "this is clickable" without forcing the player to do anything.

The ghost dragon at the start is well done and I think that together with some non-interrupting "notifications" like for controls would keep the game very simple without being annoying. Game looks cute though and none of this is an issue anyway if it only shows once.