Regarding SA 298 I was getting my texts confused. However, upon re-reading some texts I’ve made a mistake in my earlier comments. I was treating the nāmarūpa of sense processing as a newer version and nāmarūpa as external object/individual beings as the old Upanishadic version. Looking into it further it seems that even from the earliest times nāmarūpa could be understood in both senses. In ṚV 7.103.6,16 nāman is used in the sense of “designation” or “name”, thus showing nāma here as being an individual identifier. In the Chāndogyopaniṣad passage I quoted here:
सेयं देवतैक्षत हन्ताहमिमास्तिस्रो देवता अनेन जीवेनात्मनानुप्रविश्य नामरूपे व्याकरवाणीति ॥ ६.३.२ ॥
seyaṃ devataikṣata hantāhamimāstisro devatā anena jīvenātmanānupraviśya nāmarūpe vyākaravāṇīti || 6.3.2 ||
That god [Existence] decided: ‘Entering into these three deities [fire, water, and earth], as the individual self, I shall manifest myself in many names and forms’.
We see nāma with rūpa which stands for the phenomenal world of objects and beings. The manifest world of many names and forms/images. That being said, in BĀU 3.2. Yājñavalkya presents a list of the senses and their sense objects. At 3.2.3 vāc (speech) is classed as a sense with nāman as it’s object, whilst at 3.2.5 cakṣus (vision) is paired with rūpa as it’s object. Although not stated in a compound form, here we have nāmarūpa playing a role in sense experience. From the earliest times then nāmarūpa could mean individual beings/objects or it could play a role in sense processing. We see both in the suttas/agamas already mentioned. Regarding SN12.2/SA 298, with this in mind, it is entirely possible that the Sarvāstivādins were viewing it there in terms of “individual being” whilst the Theravādins were viewing it in terms of its role in sensing. Both are valid definitions of nāmarūpa, but it leaves open which is the correct definition in terms of the 12-link version of dependent origination? Given that nāmarūpa is found being defined without viññāṇa in both canons but nāmarūpa + viññāṇa is only found in some northern texts it’s possible that the northern version is a sectarian definition. That said, we do have a sutta with an āgama parallel which uses both versions of nāmarūpa (in terms of sensing and in terms of individual being) . This is DN 15, although it is noticeable that even there nāmarūpa is never defined with viññāṇa included. Instead we have a nāmarūpa which is the basis for contact through “designation & resistance contact”, thus showing it’s role in sensory processing, as well as the nāmarūpa which “grows up” thus strongly indicating the other conception of nāmarūpa as simply “name and form” or rather, “that individual”.