Do you get different prizes for winning Reflection on easy vs. hard, besides the sP amount?

It doesn't seem like it. As far as I can tell, the item prizes are obtainable from either version as long as you clear the board

I don't think they are. I used to play the hard version and used to get these regularly:

And probably some others, but those I remember in particular. Over the past year or so, I've mostly been playing the easy version and have won none of the above. I've won lots of the items below though:

You can also check out this Reflection: How did you do? v.2. They don't specify if they played on hard or easy mode, but if you check the value and moves it will indicate if they won at easy or hard. Easy: You got 9 matches, and receive 4,500 sP. Hard: You got 16 matches, and receive 12,000 sP.

I think the hard version is not limited to the top prize list, but all prizes can be won, not totally sure.

thank you!