Re: Hardest instruments to play
I think by the same token, they're all easy...if you know how.
Every instrument has different challenging aspects that are particular to that instrument alone.
For example, you might be able to play the violin, but that doesn't mean you can play the erhu, for example. which has no fingerboard, and only two strings, with the bow captive between them. It's played in an upright position. Yet its sound, and role in an orchestra or ensemble, is very similar to the violin.
Whichever one you are more familiar with is the easy one. I don't know if either one is necessarily harder.