PLEASE DO NOT PICK 
Literally just had an autofilled jungler hard int because they picked Nidalee.
Walking into lanes 2+ levels lower than the enemy laners and getting killed constantly.
are all braindead easy to the point an autofill could make them work.
/rant over
mumu should be a nice pick for autofilled junglers
kayn and Eve are pretty straight forward champs imo.
I would move Gragas, Udyr, and Volibear up to the first list. They require a bit more knowledge about their champions and jungle in general than the rest (I play none of those three btw).
But yes, do not first-time any champion or role in ranked. Have a couple champions you can play in each role before queueing up.
Since 8.10 it is not hard for a jungler to be 2 levels under a solo laner for 4-6 mins at a time. Are you suggesting to said silver jungler not to gank at all? How is it his fault they nerfed jungle exp compared to solo laners so bad?
