Azurill is obtainable in 2 ways:
1. mystery egg event
2. breeding a marril or azumarril that's holding a sea incense
if you're not to far in the game yet, you can find sea incense in a warehouse in coral ward (pre-restoration)
and for odd keystone: just keep trying, it's in there, somewhere First odd keystone took me hours, after that I sometimes 2 in a row...