No there is no commentary on Upanishads by Kashmiri Shaiva Acharya Shree Abhinavagupta. His main focus was to compile all Tantra texts which he did by writing text Tantraloka. Here are the list of his works:
As far as I know, the parimala has not been translated to English.
The sanskrit book called Brahmasutra sankara bhashya edited by N. S. Anantakrishna Sastri and Vasudev Lakshman Sastri Panshikar by Nirnayasagar Press, Bombay, 1917 includes vAcaspati's bhAmatI, amalAnanda's kalpataru and appayya dIkshita's parimala. This is the comprehensive book. The ...
It does. Imo every Purana contain atleast some interpolations.
Check verse 4:20:36-37:
"O King! When Mahādeva, being infatuated with Kāma, went into the forest of Bhṛgu and becoming naked, began to copulate, the ascetic Bhṛgu, seeing him in that state, exclaimed “O You are very shameless” and cursed Him thus :-- Let your penis drop off just now. ...