I think you figured this out already. If not, Yes it does.
Depends on the action. If you just want to have the value at index its a direct access, so the array size doesnt matter. If you do something like “is true for any” or “sorted array”, the system indeed needs to address every value in the array onces - in the best case! If the array size is n, it takes n * log(n) steps to sort the array.
Remove it by setting the value to number(0).
No.
Might be faster for the server to fail the action that checks for the vector if you replace the vector with something that is not a vector (e.g. with just 0).
As the condition property I suggest to use the “compare()” action and the “current array element”.
Example: filtered array(all players(all teams), compare(player variable(current array element, A), <, 3))
This array contains all players whos variable A is smaller than 3.
No.
“Set variable at index” sets the value at a specific index into an array. This is useful if you use a static array, for example the list of vectors you use for the orbs. They are always 10. You can address them directly and imagine them as orb1, orb2, … , orb10.
“append to array” is meant for dynamic array usage. For example, you have an array of all the players in your mode. If a player joins, you append him to the array, if he leaves, you remove him. Note that the players dont have a set index. Their index in the array can change if a player gets removed from it. So this is better to use if you have a variating amount of things to store and dont need to address them directly.