1a. you can create multiple animations for objects/buttons etc & define a default animation or none at all. using the animation > play/hide animation
action part, you can tell the engine which animation to play or hide/stop.
1b. you can also force frames with Lua using "VAnimationFirstFrame" & "VAnimationLastFrame" - using these 2 data structure commands, you can force the animation to play between a & b values you assigned.
-- animation will play between frames 2 to 5...
1c. you could also use 2 separate objects & assign a condition to the properties tab for both (one with the negate button ticked) & then you can switch between which object is active by changing the condition value between true & false.
2. Sorry, not sure what to say here... The translation from bing isn't making much sense to me.