Does a 2017 15" Macbook Pro top case fit on a 2016 Macbook Pro? The keyboard on the 2016 MacBook Pro is very prone to breaking, I've had the top case replaced twice in the past year so far and and I'm for a third time before warranty expires. Does the new 2017 top case fit on a 2016 Macbook Pro? I heard they fixed the keys in the latest iteration.

Best case they will cover it under warranty and switch to the new top case, worst case I'm considering buying a 2017 top case myself and changing.
No - the parts, keys, electronics and case cables are different.

I'd consider selling the 2016 and buying new if that's the way you want to go.