Maybe I'm too late, but I've got a nice idea to solve problem #1.
You could try replacing the condition with the
Conditional Branch - Page 4 - Script condition:
CODE
Input.trigger?(Input::C)
I don't know if this will prevent your character from keeping on sitting and resuming it's position, but give it a try, I'm rather confident in this

Why should it work? Well...
The default condition is equal to
CODE
Input.press?(Input::C)
which means "if C button is pressed and/or remain pressed, then...".
The
.trigger? condition should mean "if C button is pressed once, then...".
Anyway, if you want to make your player sit on that event, you should "stop" your player, since as I can see from your screens, it's able to move even with directional arrows, while sitting...
I hope this can help,
Jens