Ok is it necessery to complete all the necromancers tasks whlist in Act 2?

The reason i ask is becuase i have almost finished Act 2...but without using the battlefields and i am unsure of whether i am going to break main quests. I have not got the "adults becoming children " quest yet althougth,
in a pevious game i had used battlefields and got it in Act 2.

Fully patched game(version 1.47)

Thanks

Tragic