When I update a step event containing move_and_collide like this:

collider = [tilemap, obj_enemy_parent]; //all elements to collide with

move_and_collide(move_x, move_y, collider, 4, 0, 0, move_speed, -1);

it throws an error: Error:: move_and_collide::current self is not an instance

I'm not sure in which argument of the function the current self is referenced.

Plus when you don't use the 5 optional arguments in that function it throws an error saying the functions needs 8 arguments, even though they are optional.

You’ll want to use live_function_add to override the signature for move_and_collide, perhaps like so (in the end of obj_gmlive Create):

live_function_add(":move_and_collide(...)", move_and_collide)

That worked, thank you.