Will the Police file a Warrant?

My Friend's mom kept getting messages about "hey your daughter is drinking & smoking" or "her your daughter is lying to your & is w/her boyfriend not her friends", stuff like that. My friend no longer has trust or freedom from her mom. Her mom responded "Stop this" once, and they sent only one more message. Saying "your daughter is lying and with her boyfriend"
Anyways here's the question.
Can the police track down the #? (It was from a textfree app on iPhone)
&2. Will They? Is it considered good enough for a warrant?

The police really don't care about things like this.

Unless your friend has been arrested they will not file a warrant for your friend. They can start a harassment case against this said number though

The technology does exist to track that down to the exact iPhone that sent it.
The police would not care unless there was some threat of violence or blackmail involved.

If I got a text like that about my daughter, I'd figure it was some bully type person trying to get her in trouble and ignore/block the number.

I can't make sense of your garble. What I can't figure out is how your friend's mother's messages are any of your business. Anyway, warrants are not filed. They are issued by the court and they are issued when someone is to be arrested.

This doesn't really qualify as harassment and certainly doesn't warrant expending any police time on this "crime."