No, one object, two instances, it'll not increase your file size or the amount of memory being used because the system can recicle the item and simple redraw it.
Things what consume resources are events triggering as spammers and animations using frames instead of videos.
But if you go in a layout with 1.000 instances of the same object, it can increase the resources used to manage them on the event system, also, having 1 instances of 1.000 objects will increase both, the resource needed to manage it inside the event system and the memory consumption, because they are all loaded at once.
To avoid it, think how the developers did old games, breaking them in areas and inside each area you can place a bunch of different objects, targeting the amount of memory you want to use.
Avoid going up to 256MB because old mobiles have the maximum of 516MB, like MotoG, the cheapest smartphone I could remember to being able to run games =]