About the "send character and wait" action part. It is not working this way. You need to add all these action parts within a cutscene!
Example:
1. Start cutscene
2. Send character TO XY and wait
3. End cutscene
Aye Thomas is correct here. Players can still interact with the game. The wait until x action parts are only pausing the actions in the action block they are created in, they do not pause the game / prevent the player from being able to click a new destination, object, item or character etc. To do that you need to use 1 of 3 methods.
1. use a begin/end cutscene wrapper (all action parts inside can be skipped with ESC key)
2. use a hide/show cursor wrapper (same as cutscene wrapper, but can't be skipped)
3. create an overlay interface that is the same size as your default game resolution & show/hide as needed - doesn't hide the cursor, but prevents everything underneath the interface from being clicked on.
I should think using openGL shaders on iOS/android games wouldn't be the best of ideas to begin with. Handheld games need to be well optimized & kept as small as possible. Shaders will eat into the available system resources.