Hi! I adress some of this, particularly the Indian narratives, here and you might be interested in the other answers on my flair profile. Essentially, the famous Qissah-i-Sanjan was only composed in 1599, during the reign of Padishah Akbar. Its narrative probably reflects the earlier tensions between the Delhi sultanate and the native populations of Gujarat (possibly in contrast to the more tolerant Mughal emperors, esp. considering it was composed in Persian?), rather than the Muslim conquests of Persia it purports to describe. The other source, the Sanskrit Slokas, were probably written by a Hindu Brahmin who had only superficial familiarity with Zoroastrianism.

I'll have to check my sources and see if I have access to some of the primary Iranian sources to see if I can give you a full answer to that part of the question, if so I'll probably have it up in 12-16 hours. Feel free to field any followup or further questions in the mean time!

Well, there isn't a whole lot I can find, but I'll summarize some important points.

Boyce's Textual Sources has a pretty interesting history from Sistan, written down in 1060 AD, about an incident that occurred during the reign of Mu'awiya in the 7th century. Mu'awiya appointed a governor, Ziyad, who sent a delegate, 'Obayd Allah, to kill Shabur, the chief priest of Sistan, and stamp out their fires. Upon hearing of this, the Muslims of Sistan were alarmed, and objected that surely neither Muhammad nor the Rashidun Caliphs had ever done such a thing, and that this was against their agreement with the Zoroastrians. So they wrote to the court in Damascus, and received a fatwa that they were to abide by a treaty of friendship with the Zoroastrians, for they had explained that they did not worship the fires or the sun, and that these were merely their altars, like the altars of a Mosque - and that they should instead regard them as fellow worshippers of God.

Obviously, this event cannot be assumed to be historical, nor does it reflect the attitudes of all Muslims in Persia at all times, but it suggests a degree of mutual understanding that seems to go against the idea of the conquests as a universal cataclysm. A ninth century text in a similar vein discusses how Umar accepted tribute from Azerbaijani Zoroastrians with the conditions that he would let them worship in peace.

Of course, those texts are from the Muslim point of view. There are also some fifteenth-century letters from Iranis to Parsis. These concern legal judgments within the communities rather than history, but they do mention the present "age of wrath" as worse than even what followed the conquests of the "Greek Alexander". There's a milennarian tone, with a formulaic-looking declaration that the three Saoshyant (Bringers of Benefit) will surely arrive to deliver justice upon the evildoers in the world.

I don't have any good sources on how Iranis in more modern times have viewed the original conquests (what I have on modern Iran is mostly just stuff concerning their legal status, etc), but it is worth noting that they suffered significant oppression in Safavid and Qajar times, including forced (swordpoint) conversions in the 17th century; Qajari persecution (central and local; Boyce notes that the most dangerous time was "between the death of one king and the crowning of the next", due to the weakening of central authority) was bad enough to prompt many Iranis to migrate to India. Their tradition seems to have persistently been, per European accounts, that if they would endure this time of hardship, their faith would once again be restored to glory, as it had been after the conquests of Alexander. It is hard to see that melding with a positive view of the conquests, even though it is certainly possible that cultural memory of less radical Muslim rulers survived.