Yes, and overlapping is already every tick by definition. Collisions are for a single trigger.
Yes, all objects have collisions enabled by default. If you want to stop them offscreen use else.
You might also try a different approach of not using collisions at all.
The array object can mimic a grid of objects, and can simplify comparisons.
value of arrayAt(1,1) > arrayAt(1,2) etc.
You just have to worry about picking objects after that. In which case instance variables work well.