Folks, I know neither Arabic nor Parsi though I’ve been around both a little. A very little. Still many of the terms here somehow sound to me like they are Arabic and not Parsi. Are they, or are they not?
I'll give you my take: Yes, they are Arabic & have Arabic root such as: "walayat faqih", "ummah", "fasl el-khitab".
Then again, "Parsi" became "Farsi" initially after Arab-Muslim invasion of Iran (7th century), as you may already know. I think it would be fair to say that even the ShahNameh (written circa late 10th/early 11th century, during the Iranian Samanid Dynasty) is only about 97% in Parsi of the pre-Islamic era. The other 3% or so is still influenced by Arabic.
The Persian language has evolved over time, and over many centuries. Modern Persian (Farsi) even includes words/expressions from French, Turkish, etc... but, mostly, Arabic roots.
In brief, the Khomeinist Rule is, essentially, a re-invented Arabic, Islamic Rule, re-introducing many Arabic-based words into what is known as "Parsi" (Persian language) - some words/expressions are actually "mullah/regime invented" words & expressions too, often, not in the recent non-mullah lexicon.
I think, FARS probably would know more about the linguistic nature?