Sasuke wasn't a copy ninja, he was a close combatant .So far that only apply to Kakashi who was capable of adapting all of the elements hence why he was renowned as the copy ninja. Sasuke was never able to use any more nature other than fire and lightning. The same thing apply to Itachi despite he was famed as a greatest genius, he's only limited to 3 natures.
And when he did copy he copy the nature, hence chidori, Sasukes nature was fire only in part 1 .
Itachi wasn't really limited either, he was just exposed to water fire and earth?
And frankly it wasn't his style to copy,
And assuming you are correct , Sarada as a newly academy graduate has two natures, so by time she is a chunnin , she could possibly have them all.
Fire , lightening, yin and probably yang too