Dua 1
اَللّٰهُمَّ اَعِذْهُ مِنْ عَذَابِ الْقَبْرِ
O Allah! Protect him from the punishment of the grave.
Sahih Mawquf: Muwatta' Malik, ed. Abd al-Baqi (1/228), the wording is his, Musannaf Ibn Abi Shaybah, ed. ash-Shathri, no. (11936), and al-Albani graded it Sahih in his research on al-Mishkat, no. (1689).
This narration says that Sa'id bin al-Musayyib (RH) said: I prayed the funeral prayer behind Abu Hurairah (RA) over a child who had not yet committed any sin, and Abu Hurairah (RA) said these words in the supplication.
It is established that this supplication is also said, along with a long supplication, at the funeral of adults; see page (148) of this book.