Did Adi Shankaracharya accept equality of 5 major gods in his works?
Since you believe the Stotrams attributed to Adi Shankara are later works, I guess then it will be difficult to prove that he believed all the Panchatayana deities as Saguna Brahman. This is because his major works only refer to Sriman Narayana as supreme alone.
For example, his Bhagavad Gita commentary states that nobody is equal to Sriman Narayana:
Asi, You are; pita, the Father, the Progenitor; lokasya, off all beings; cara-acarasya, moving and nonmoving. Not only are Yur are Father of this world, You are also pujyah, worthy of worship; since You are the guruh, Teacher; [He is the Teacher since He introduce the line of teachers of what is virtue and vice, and of the knowledge of the Self. And He is greater than a teacher because He is the teacher even of Hiranyagarbha and others.] gariyan, greater (than a teacher). How are You greater? In answer he says: Asti, there is; na, none other; tvat-samah, equal to You; for there is no possibility of two Gods. Because all dealings will come to naught if there be many Gods! When there is no possibility of another being equal toYou, kutah eva, how at all; can there be anyah, anyone; abhyadhikah, greater; api, even; loka- traye, in all the three worlds; apratima-prabhavah, O you of unrivalled power? That by which something is measured is pratima. You who have no measure for Your power (prabhava) are a pratima-prabhavah. Apratima-prabhava means 'O You of limitless power!' Since this is so, (Adi Shankara's commentary on Bhagavad Gita 11.43)
In Bhagavad Gita 9.25, he explicity states that worshipping other deities is not the same as worshipping Vishnu:
Deva-vratah, votaries of the gods, those whose religious observances [Making offerings and presents, circumambulation, bowing down, etc.] and devotion are directed to the gods; yanti, reach, go to; devan, the gods. Pitr-vratah, the votaries of the manes, those who are occupied with such rites as obsequies etc., who are devoted to the manes; go pitrn, to the manes such as Agnisvatta and others. Bhutejyah, the Beings such as Vinayaka, the group of Sixteen (divine) Mothers, the Four Sisters, and others. And madyajinah, those who worship Me, those who are given to worshipping Me, the devotees of Visnu; reach mam, Me alone. Although the effort (involved) is the same, still owing to ingorance they do not worship Me exclusively. Thereby they attain lesser results. This is the meaning. 'Not only do My devotees get the everlasting result in the form of non-return (to this world), but My worship also is easy.' How? (Adi Shankara's commentary on Bhagavad Gita 9.25)
Again, in Bhagavad Gita 6.47, he clearly differentiates meditation on Rudra (Shiva) and Aditya (Surya) from meditation on Vasudeva (Vishnu) and even terms the latter superior:
Api, even; sarvesam yoginam, among all the yogis, among those who are immersed in meditation on Rudra, Aditya, and others; yah, he who; bhajate, adores; mam, Me; antaratmana,with his mind; madgatena, fixed on Me, concentrated on Me who am Vasudeva; and sraddhavan, with faith, becoming filled with faith; sah, he; is matah, considered; me, by Me; to be yukta-tamah, the best of the yogis, engaged in Yoga most intensely. [It has been shown thus far that Karma-yoga has monasticism as its ultimate culmination. And in the course of expounding Dhyana-yoga together with its ausxiliaries, and instructing about the means to control the mind, the Lord rules out the possibility of absolute ruin for a person fallen from Yoga. He has also stated that steadfastness in Knowledge is for a man who knows the meaning of the word tvam (thou) (in 'Thou are That'). All these instructions amount to declaring that Liberation comes from the knowledge of the great Upanisadic saying, 'Thou art That.']
In Bhagavad Gita 7.20, he says people who worship deities other than Vasudeva lack wisdom:
People, hrta-jnanah, deprived of their wisdom, deprived of their discriminating knowledge; taih taih kamaih, by desires for various objects, such as progeny, cattle, heaven, etc.; and niyatah, guided, compelled; svaya prakrtya, by their own nature, by particular tendencies gathered in the past lives; prapadyante, resort; anya-devatah, to other deities, who are different from Vasudeva, the Self; asthaya, following taking the help of; tam tam niyamam,the relevant methods-those processes that are well known for the adoration of the concerned deities.
In his commentary on Brahma Sutras 1.2.17, he once again explicitly states that Surya cannot be regarded as supreme:
Selfhood cannot be ascribed to the sun, on account of his externality (parâgrûpatva). Immortality,&c. also cannot be predicated of him, as Scripture speaks of his origin and his dissolution. For the (so-called) deathlessness of the gods only means their (comparatively) long existence. And their lordly power also is based on the highest Lord and does not naturally belong to them; as the mantra declares, 'From terror of it (Brahman) the wind blows, from terror the sun rises; from terror of it Agni and Indra, yea, Death runs as the fifth.'--Hence the person in the eye must be viewed as the highest Lord only.
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