I do not agree that we are in "Satan's Little Season." I can dig up some podcast references on this, and I think that one in particularly put the complete kibosh on that notion for me.
1. What is your issue with the Book of Enoch? I have very little issues with the first of the four parts, since that is directly quoted by Jude and Jesus direction in cannon scripture. I do have quite a lot of issues with the gnostic BS in Enoch 3/4. I am still poking at 2.
2. I very much disagree, as my understanding of the Hebrew words used do not refer to a Human, though, as you have correctly stated that "Ahshatan" is a job title, and NOT specifically a particular being, much like the very misunderstood title "angel" (which simply means messenger, with a few caveats and addendums). However, I have never once in all my reading ever come across the notion that this was a Human. I am curious as to how you have come to this conclusion.
3. Nope. 100% disagree. It seems that you have completely missed out on the parts of the OT that explicitly state that God gave authority to various other beings (little g gods is my best understanding) who then failed to govern rightly. This is explicitly stated in the OT. (I will find the exact reference later, if you don't know it already.) There is, consistently and throughout the OT and into the NT, one specific being who has been trying to usurp God and throw wrenches into his His plan. You really should look up the "Serpent Seed" framing of the entire Biblical narrative. This one idea/thread brings so much focus to many of the lesser understood parts of the Biblical narrative, and it is a shame that it has some rather unsavory adherents that twisted it into things like racism and eugenics, as when taken in a proper Biblical context it explains a heck of a lot about evil in this world.
But to answer your specific question: God had given authority to other gods, and one of them, specifically, was referred to, by Jesus, if I am not mistaken, as "The god of this world." So . . . Why in the world would that being NOT have the authority to give to Jesus everything in his authority? Granted, I think that is a bit silly to do, but, hey . . . I do not take the Adversary entirely seriously all the time, even if he is serious business.
Also, Jesus had not entered his position of Ultimate Authority at that time, though I am sure that this could be debated. And, your position also ignores the temptations' purpose. If this was NOT another being tempting Jesus, then it completely undermines Jesus' purpose. If that is the case, then there is no point in believing in Jesus as our Lord and Savior.
I will have to percolate on your final sub-bullet of that point. The first thing that pops into my head is relating to "the flesh" which is definitely "within" as you say, but, that does not mean that there is no external evil, as 1 Peter 5:8 says "Be of sober spirit, be on the alert. Your adversary, the devil, prowls around like a roaring lion, seeking someone to devour." So, you, specifically, Niel, have an adversary looking to devour you. Unless you want to argue with Peter, which, even an idiot like me might not exactly want to do . . .
4. Absolutely not. Point blank, this is probably the dumbest thing I have ever read from you and is not at all justifiable in any context within the Biblical narrative and is only possible if you ignore, well, everything else in the Bible. Since you were so short with this one, I don't even know where to contextually begin with this, other than that is not actually even possible if you dig into the Hebrew, even a tiny bit.