Vibs
Excellent description. However, I must have one of my rare disagreements with you on one point.
Vibhishan did become king of the Rakshashas: they were the inhabitants of Lanka. It's noteworthy that Rama didn't return Lanka to Kubera and his Yakshas (?) You are right that there were only a few left. But the ones killed in Krishna avatar don't seem to have dated back from treta yuga - not Narakasura, not Banasura (who wasn't killed), not Shambara, and neither any of the ones killed by Bhima - not Bakasura, not Hidimba, not Kirmira, not Alambusa. So Rama did not wipe out the rakshashas.
The only reason for killing Kumbhakarna was the Jaya/Vijaya curse - other than that, Kumbhakarna was relatively harmless, and only did whatever he did on the day he'd wake up at Ravan's behest. I don't fully agree with Godisone that it was as necessary to kill Indrajit & Kumbhakarna as it was to kill Ravan - just that it was impossible to do it. Indrajit was not noted as a bully - his war against Indra was one to save his father, rather than conquer Devalok, and I have a theory that only a virtuous soul attains a pativrata stri like Sulochana, who ranks right up there with Sita, Savitri, Anusuya, et al (and above Kaushalya, Draupadi, Mandodari, among others) More to the original point, it was impossible to kill Ravan there just by Sita's touching him.
That brings to mind another side question. In this serial, when Ravan is talked out of taking on Rama directly by Akampana and Vibhishan, Mandodari, in her anger later at Shurpanakha, tells her that if Ravan were to engage Rama in combat, he'd definitely win. Vibhishan too seemed to alude to that somewhat reluctantly, as he agreed with Akampana that winning a combat against Rama would not bring him any glory, since Rama was a mere mortal (a bizzare argument, given that Rama had just wiped out Khar and Dushan). Does anybody actually think that Mandodari & Vibhishan was right, and that if Ravan had gone there with just Indrajit (to take on Lakshman), Shurpanakha (to abduct Sita) and a few more warriors, like, say, Atikaya, that Rama would have prevailed against them? In other words, was the abduction of Sita (aside from fulfilling Vedavati's curse) a necessary pre-requisite for Rama to be victorious against Ravan?
I'd think that Rama being a mortal would be enough, but I'm interested to hear how many think Ravan would have prevailed, particularly since he did suffer defeats in the past, including a stalemate with Rama's ancestor Mandhata.