Yes. Picking an object by UID is pretty fundamental and the link I posted above has the details.
edit: the yes is for the first part of the question. The second part is 'no', but see below for how to do it.
If you have two different sprite types then you'll need to add them to a Family, then pick Family by UID in the function.
If I get a sec I'll do a capx.
edit: hope this helps. You'll see if you select Sprite1, then try and change it's size using ResizeASprite2() function, it won't resize (same with Sprite2 and ResizeASprite1()). If you use the ResizeSpriteByFamily() function you can click either type and it will still work.
edit: tiny update to capx so you can keep resizing until the cows come home