Auto generating slug with custom fields or ID
I think for this you'd want to write a custom plugin that listened to the onSaveEntry event.

That plugin would check that the given entry is in the correct section/entry type you're interested in, pull any data from custom fields set on the entry update the slug for that entry accordingly.

I'd probably look at updating the slug directly in the database and avoid going back through craft()-&gt;entries-&gt;saveEntry() to avoid getting into an infinite save entry loop.