7X7 clearly a Midrash

The קליר writes in the יוצר לפ' פרה ----דרושה בזקוק שבעה משבעה , הזיות It is based on Tehillim #12 אמרות ה' -- מזקק שבעתים  The Midrash enumerates the 7X7 referring to the פרה אדומה 1) 7 פרות 2) 7 שרפות 3) 7 הזיות 4) 7 כיבוסין 5) 7 טמאים 6) 7 טהורים 7) 7 כהנים

פ"א-Parshas Porah

The Mechaber (O.Ch. 685:7) writes :

Some say that reading Parshas Zachor & Parshas Parah is Min Hatorah.

The Mishna Verurah writes that many Achronim argue and hold Parshas Parah is not Min Hatorah.

Tosfos (Brachos 13a & Megilla 17b) enumerates the times when Kerias Hatorah is Min Hatorah.
The original Girsa in Tosfos had Parshas Para as a Keriah Mideorysa.

The Maharshal removed from Tosfos "Parshas Parah"  and says it was  mistakenly put in.

The Mekor Baruch (R.Baruch Epstein z"l) writes it'spossible the mistake came about by Tosfos saying Parshas Zachor is Deorysa פ"א Tosfos meant. to read Parshas Zachor פעם אחת  once a year. 

People mistakenly thought it meant פרה אדומה