The same classification is found in MN.9 too. If you look at MN.18, contact is the meeting of consciousness, senses and sense stimuli. (tiṇṇaṃ saṅgati phasso). In DN.15 the first two links of DO are not found. And in it, there is a reciprocal relationship between consciousness and name & form. In SN 12.67 this reciprocity is compared to two bundles of reeds leaning up against each other.
So how are we to understand all this?. Let me give it a try. Hopefully it will address your query;
DN. 15 says;
“It was said: ‘With name & form as condition there is contact. How that is so, Ānanda, should be understood in this way: If those features, traits, signs, and indicators (ākāra, liṅga, nimitta, uddesa) through which there is a description of the mental phenomena (nāmakāya) were all absent, would designation-contact (adhivacanasamphasso) be discerned for the physical phenomena (rūpakaya)?
Certainly not, venerable sir.
If those features, traits, signs, and indicators (ākāra, liṅga, nimitta, uddesa) through which there is a description of the physical phenomena were all absent, would impingement-contact (paṭighasamphasso) be discerned in the mental phenomena?
Certainly not, venerable sir.”
Let’s start with ākāra, liṅga, nimitta, uddesa translated respectively as features, traits, signs, and brief descriptions, which according to the Sutta are found in relation to both nāmakāya and rūpakaya respectively translated as mental phenomena and physical phenomena.
Form is the four great elements of earth, water, heat and air. Form is also the form derived from the four great elements. This means that form is basically the physical objects but because of their features, traits, signs and descriptions a mental image is constructed when senses come into contact with them. This mental image is the form derived from the four great elements.
So when for example an object enters the vision path of the eye, because of the features and traits etc. of that object, the mental image rupa takes place while simultaneously nama factors such as feeling, perception, intention and attention too take place. This is the contact which is a crisscrossing between nama & rupa. This means that contact is a hybrid of nama & rupa and this whole process is known by consciousness. In fact this process is nothing but experience and DO regardless of various interpretations must begin here because it is the experience we all grasp with craving mistaking the consciousness as (our) self.
Vinnana does not cease for an Arahant but rather, as you have stated, it is the attachment to the five aggregates of experience that has ceased. This means Arahants do experience but their mind or consciousness or thoughts do not station on any rupa because they have understood that consciousness which normally gets enticed by the features and traits of rupa is like a magician. Anidassana Vinnana is this mental state of freedom from all sense desires.
This is why MN.43 also says that consciousness needs to be understood and wisdom needs to be developed. Developing wisdom means understanding the consciousness as a dependently arisen phenomena rather than as a self. All attachments take place due to lack of this understanding.
If you go deep into the four establishments of mindfulness in DN.22, it is designed with the objective of freeing consciousness from stationing on the four establishments which represent all possible objects where consciousness, mind or thoughts can possibly station with craving or attachment.
With Metta