Yes, both mountains can exist on two seperate sheets, but be on the same layer.
Yes and No. If you have the MOUNTAIN layer THAWED (unlocked) you can edit all the mountains. If you ONLY want to play with the mountains on sheet 1, you must HIDE sheet 2 (you cannt look sheets), and thus you cannot see or touch the mountains on sheet 2, even though they are on the same layer.By selecting the mountain layer you can edit all the mountains regardless of what sheet they are on. By selecting sheet 1 you can edit mountain 'a' only and by selecting sheet 2 you can edit mountain 'b' only... is that right?