I think a pair of cheap (thin) snow/ski pants will be a better option than fussing with all those pads. They won't restrict her movement very much. The fabric is slippery, so she'll slide a bit during falls, which will help lessen the impact.
The plastic knee pads are really not good for ice skating. The plastic outer shell slides badly when it hits the ice, differently than snow pants, so forward falls usually turn into face plants. Plus, as Skittl says, it's hard to get up when you can't balance on your knees. You're right: they're to prevent road rash, lol. While you can get scraped up from the ice, it's not half as bad as asphalt or even wood.
With warmer weather coming, keep the snow pants in the car and pull them on over whatever she's wearing to go skating. The pants are water resistant, so she'll stay warm on the ice, even with a lot of falls. When she's done, take them off and leave them to air dry in the car for the next outing, and then go home with a dry seat, lol.
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