OCF 234 through 342 are devoted to special texts and adaptations for the funerals of children, including infants. This shouldn’t be surprising considering the post-conciliar reforms designed to direct rituals for common practices (Baptism) for children, as well as a nod to accessibility (Lectionary and Eucharistic Prayers for Masses with Children).
48. Part II, “Funeral Rites for Children,” provides an adaptation of the principal rites in Part I: “Vigil for a Deceased Child,” “Funeral Liturgy,” and “Rite of Committal.” These rites may be used in the funerals of infants and young children, including those of early school age. The rites in Part II include texts for use in the case of a baptized child and in the case of a child who died before baptism.
The modern priest and pastoral ministers do not function on autopilot. The OCF presumes a minister will be familiar with the whole book of rites, not just the bookmarked pages. I believe a parish liturgist should be familiar with the book cover to cover, and be prepared to guide someone who lacks a specialty in liturgy.
The rest of OCF 48 provides for an adaptation. Read through it and comment on when you think such an adaptation might be appropriate:
In some instances, for example, the death of an infant, the vigil and funeral liturgy may not be appropriate. Only the rite of committal and perhaps one of the forms of prayer with the family as provided in “Related Rites and Prayers” may be desirable. Part II does not contain “Related Rites and Prayers,” but the rites from Part I may be adapted.
Note that the text says vigil and funeral may not be appropriate. My sense is to assume they are unless the particular situation might suggest otherwise. When do you suppose such situations might arise?