Very good article. That is the truth indeed. For the same reson Vyasa has depicted the same story for Shiva in Shiva Purana, Skanda Purana (Suta Samhita) and also in Devi Bhagawatam. Had he been a bigot he would have not included Kenopanishad story in Shiva and Shakti related puranas.
The Vidyaranya swamy’s verse from Anubhuti Prakasha which you quoted as:
//Intent upon obtaining the grace of Ishvara, Indra stood there fixing his gaze on the sky. Then, with a view to bless him , Hara took upon the form of Uma//
The same has been explained by Sri Samavedam Shanmukha Sharma gurugaru during his pravachanam on Uma Sahasram and said,
“Indrudini choosi Parameshwarudiki daya puttindi ta …parameshwarudu ki daya pudite aayana aavida (uma) ga maaripotadu ta” meaning, “when Shiva saw Indra, he became compassionate on him, and when parameshwara becomes kind , he becomes the mother (uma)”.
Just your point reminded me of this pravachanam so posted it here. 🙂
शंकरं शंकराचार्यं केशवं बादरायणम् ।
सूत्रभाष्यकृतौ बन्दे भगवन्तौ पुनः पुनः ॥
[Obeisance to Shiva and Keshava who incarnated as Shankaracharya and Badarayana (Vyasa) and composed the commentary and the Brahma Sutras respectively.]