Are the rituals like anta-yatra, agni sanskar, pindi- dan, tri-pindi shraddha and narayan nag bali mentioned specifically in pre manusmriti texts?
I do not know about the dating of texts, but yes Preta Kanda of Garuda Purana discusses elaborately the rituals one has to do after a person's demise. Here are a few lines from Garuda Purana
When it is ascertained that life has gone out of the body, the son should bathe and wash the corpse with pure water without delay.
The corpse should be laid lightly on earth with its head to the south.
O bird, preta pinda is given inorder to comfort the deceased.
The ten day period of asaucha has been prescribed for the relatives on the father side.
Even other puranas like Padma Purana, Markandeya Purana etc talk about Sraddha ceremony.
Hope this helps you.