1) Most schools will have direct access to your DAT scores. So most of the time, you won't have to worry about that.
2) Yes. However, AADSAS won't send out your application until they receive your transcripts. You'll need to print out the transcript matching forms and give them to your university to order the transcripts.
3) Yes, AADSAS will send out your application but it's still considered incomplete by dental schools. They need everything to evaluate your application.