देवेषु विश्वासटिप्पन्यः

Embodiment in text

In one point of view, the dEvatAs are actually concepts (and associated powers) which exist in the form of mantras and even entire texts - see citations in V’s mantra page).
Consonance with modern views - Vishwa Adluri - “Rama is in the rAmAyaNa” YT, AR.
“रसो वै सः” इति श्रुतिः।

Sound-body consciousness

Via MT:
I would say the mantra-s are conscious (rather than living) with shabda-tanu just as a living being is conscious with an ANava-tanu. The other sounds are conscious too just as a stone or dead wood is conscious but they are almost entirely of the guNa tamas.

However, a mantra like a living organism has the additional enrichment of sattva which impinges on that consciousness. That makes them different from just a random sound. That sattva in the mantra is seen in the form of its Chandas, bIja combination and other features which map to the deity of the mantra. That’s why I’m an opponent of the kautsa thought.

Finally, I’d add the same concept also extends to yantra-s: what distinguishes them from a random assortment of points or lines. This widely used in sAdhanA by the erudite sAdhaka-s but the theory was less developed in most popular traditional sources as H tended to focus more on the linguistic side.

In mImAmsA

In Mimamsa-Sutra in its commentary, God has not been the subject-matter of discussion. But in the ’Devatadhikarana of Mimamsa-Sutra it has been shown that the Mimamsakas accept the God or deity ‘sun’ (suryadevata). To the Mimamsakas, this deity is ‘sabdamayi’ or ‘mantramayi’, to whom the sacrificial oblations are offered, and who is invoked or praised in the vedic chants. In other words, sacrifices or rituals are neither complete no fulfilled if there is no God. One cannot enjoy the rewards or effects of a sacrifice unless the deity or God accepts the sacrificial substances in a proper manner. Of course, sacrifice and religious rites are of great importance asthey constitute main subject matter; while offerings God (deity) etc. are subsidiary to the sacrificial rites. {DC}

शैवतन्त्रेषु

“They are deities embodied in the form of objects or sounds. When one receives a mantra from an ācārya/guru (a teacher), having received proper initiation, and recites every letter of it with caution and competence, he is manifesting that very mantradevata (mantra-deity) in his mind and body, and receives the grace of that deity in the form of sound. The same goes for the very texts themselves: कामिकं पादयुग्मं स्याद्योगजं गुल्फमेव च। चिन्त्यं पादाङ्गुलिः प्रोक्तः कारणं जङ्घिका भवेत्॥” {GA18}

raurava-tantra: न मीमांस्या विचार्या वा मन्त्राः स्वल्पधिया नरैः।
प्रमाणमागमं कृत्वा श्रद्धातव्यं हितैषिभिः॥
सर्वे मन्त्रात्मक देवास् सर्वे मन्त्राः शिवात्मकाः।
शिवात्मकमिदं ज्ञात्वैवमेवानुचिन्तयेत्॥ …
यावन्तो रुद्रदेवाश्च रक्षो-यक्ष-महेश्वराः।
तावन् मन्त्राः समाख्यातस्
तेषाम् सङ्ख्या न विद्यते॥
देशभाषा-निबद्धाश्च
दिव्याक्षरपदैर्युताः।
सर्वज्ञाः सर्वगाः शुद्धाः
सर्वे सर्वज्ञ भाविताः॥"

parAkhya tantra TW. mantreshvaras/ vidyeshvaras as embodied aspects of brahman TW, associated with particular mantra-s. The vidyesha-s are denied union with brahman just so that they can uplift us, and are therefore quite disgusted by the world (and irritable). Knowledge of this embodiment makes reverence and formality surrounding a mantra common-sense.

Liberation of mantra-s

pauṣkara āgama states:
अष्टाव् अनन्तसूक्ष्माद्याः यथापूर्वं गुणाधिकाः।
अतिसौन्दर्यलावण्या अक्षीणमनसस् सदा॥
विद्या विद्याह्वयं प्राप्तास् संख्यायास् सप्तकोटयः।
प्रशान्तकलुषास् सर्वे महात्मानोऽमितौजसः॥
एतेषां यस्य वैराग्यमुपजातं महात्मनः।
किम् एतेन+अधिकारेण श्रेयसः परिपन्थिनः॥
इति तं परमेशानो मलपाकमपेक्ष्य सः।
स्वेच्छयैवानुगृह्णाति मुक्तिव्यक्त्यर्थयादृशा॥
ततो मुक्त्यर्थमासन्नं कनिष्ठं तत्पदे विभुः।
नियुनक्त्यनुगृह्यान्यं तत्पदे नियुनक्त्यपि॥

Eight [Vidyeśvara-s]: Ananta, Sūkṣma and others; each preceding one possesses one more [divine] characteristic; they are of tremendous beauty and loveliness, they are of an ever-undiminishing mind. The Vidyā-s (another name for the mantra-s) have attained [the plane of the] Vidyā (referring to the transcendental śuddhavidyā plane discussed above); they number about seventy million. With their impurities extinguished/abated, they (the seventy million) are all great souls, of boundless strength. Of them (the mantra-s), whose dispassion has originated, [that one] is a great soul; “What with this authority (high office of being a mantra), obstructing the [greatest] good?” Thus, [seeing this dispassion for authority], Parameśāna (Śiva), considering that mantra’s [highly] mature state; he, of his own will, confers grace on any mantra closest to mukti (liberation); furthermore, the one in the smallest proximity for obtaining mukti, the lord [places that mantra] in the place [previously held by the mantra which just got liberated]. He appoints [a mantra] for liberation; he appoints another [mantra] for that [vacant] position.”

वैष्णवतन्त्रेषु

पौष्करसंहितायां विस्तारेण कथितम्।

There are empowered souls on the path to mokSha that are delegated various cosmological tasks (e.g., the vidyeshvara-s).

Then there are those who have attained mokSha/shivatvam who may no longer do any work since they won’t do anything impelled by desire. Do they then do anything spontaneously? I’m not sure. They are all-pervasive like the Śiva & also bear all of existence within themselves.