2 - No this will not increase performance. All this will do is force the system to test each object each tick to see if it is on screen which would in fact hurt your performance. If you have a really big game with a large number of static objects, you may want to look into enabling Render Cells.
4 - The pin behavior can have the same result as the set position to object but also has the added benefit of getting rotation from the object pinned to. Also, it is optimized so would cut down on performance issues.
5 - In almost all cases, using time is better than every tick. Every tick can cause issues because different systems will register a different number of ticks per second.
7 - You can use more than one else. However, it is only valid immediately following a single easily defined event trigger. Else just means if the last event didn't fire, trigger this event. You can combine an else statement with another condition to create an "Else If" event and have any number of these in sequence followed by i final "Else." See the else section of the tutorial at the following link for more information:https://www.scirra.com/tutorials/292/gu ... t-features