It is generally told that the 4th entry in the chain of Dependent Origination, namely Nama-rupa is nothing but the Five Aggregates (Nama being the sum of Vedana, Sanna, Sankhara and Vinnana). But three of the Aggregates separately appear in the chain of Dependent Origination : Sankhara (2nd entry), Vinnana (3rd entry) and Vedana (7th entry). So there occur three repetitions if Nama-rupa is identical with Five Aggregates. How can this be explained?
Due to past fabrication resulting from past experiences is instruments in creating the current conciousness. As conciousness cannot exist without a body this creates current body with each of the relevant sense faculties associated with the different consciousness.
The faculties in the current body which come in contact with external objects. The conciousness experiences and identifies the external objects based on the sensation of the touch these and our perception reacts with like, dislike and neutral metal action.
These current reaction creates more fabrication which keeps the above cycle going in the future. The reaction is that of our perception classifying sensations into pleasing, unpleasant and neutral sensations of which we want more or less.
The 5 Aggregates is the same as Nama Rupa. Different parts of the aggregates appear in different places in DO to illustrate the above cycle base on which aggregate is in active in the relevant part of the process. DO is not always depicted in the 12 link form; for further details see Dependent Arising by Piya Tan.
DN15 is aprophyca. It fails the Buddhist Great Standards (Mahapadesa) and therefore should be dismissed as being the words of the Buddha. The Pali scriptures state consciousness is only the six sensory consciousness (eg. MN 148). They state consciousness is only cognition (eg. MN 43). The idea of 'relinking consciousness' was obviously created after the Buddha, by religious clerics.
Sankhara in the five aggregates can include neutral mental formations as well. But Sankhara as in Avijja paccaya Sankhara refers specifically to Karma.
Vinnana in the five aggregates can be any of the 6 types of consciousnesses. Eye consciousness, ear consciousness, nose consciousness etc. depending on the sense that is active. But Vinnana as in Sankhara Paccaya Vinnana is just the Patisandhi Citta. Only the mind consciousness is present at that point.
Vedana as in Passa paccaya Vedana can be Vedana caused at any of the 6 sense doors. But before the sense doors are created, Nama-rupa is just the embryo accompanied by a stream of Bhavanga cittas with the birth Karma as the object. The vedana there is caused by the birth Karma instead of contact at the 6 senses. More info here.
In fact, all entries in Paticcasamuppada belong to the five aggregates or the nama-rupa. But Paticcasamuppada uses specific instances to explain the process of causes and effects that leads to suffering. So it doesn't qualify as repetition.
Namarupa is defined in the scriptures. Nama is feeling, perception, intention, internal contact & attention. Rupa is the physical body composed of earth, wind, fire & water elements.
Dependent origination is not 'Creationism' explaining how human life comes into physical existence.
Dependent origination explains how ignorance conditions the five aggregates to generate psychological suffering.
Therefore, the five aggregates will repeatedly be mentioned in the 12 conditions as the conditioning of suffering moves from subtle to gross.
Ignorance conditions internal feelings, perceptions, thoughts & bodily drives (sankhara) which condition the consciousness & namarupa to purse outer sense objects, which then condition grosser feeling, craving, attachment, ego-becoming, self-identity ('jati') and the aging-&-death of the self-identity, which results in suffering (sorrow, lamentation, pain, grief & despair).