Tutoyering in The Lord of the Rings

I've just spent a week or three reading and re-reading "The Battle of the Pelennor Fields," in which (among other things) the Witch-king tutoyers Éowyn and she sticks quite firmly to the formal you-form, thank-you-very-much:

‘Come not between the Nazgûl and his prey! Or he will not slay thee in thy turn. He will bear thee away to the houses of lamentation, beyond all darkness, where thy flesh shall be devoured, and thy shrivelled mind be left naked to the Lidless Eye.’ 

 A sword rang as it was drawn. ‘Do what you will; but I will hinder it, if I may.’ 

‘Hinder me? Thou fool. No living man may hinder me!’

[...] ‘But no living man am I! You look upon a woman. Éowyn I am, Éomund’s daughter. You stand between me and my lord and kin. Begone, if you be not deathless! For living or dark undead, I will smite you, if you touch him.’ 

So I've now searched LotR for all instances of thou (22), thee (33), thy (24), and thine (2), and created two character network maps to show the results.

Figure 1 maps out spoken (unsung) tutoyering between "contemporary" characters during the course of the story (even if the message is conveyed via a third party).  (Update: A color-coded version is now available.)

Fig. 1:  Who's Tutoyering Whom? 

Figure 2 shows the tutoyering in song and story.  The first two are "contemporaneous" with the action in the secondary world: 

• Top left is the elves' hymn to Elbereth, which Frodo et al. overhear in the woods (they do not seem to be the intended audience).  
• Top right, if I recall correctly, is the song Frodo hears and remembers as he's leaving Lothlorien and translates many years later; I have lazily assumed the thous were addressed to him specifically, the way these magic elf-songs form in one's mind.

The next three involve tutoyering between the characters within songs or stories sung or told by our lovable secondary world characters.  Here, the speaker or singer is linked via a double dark line to a sort of cartouche containing his song or story, and directional arrows connect the cartouche with his intended audience. The tutoyering is shown within the cartouche.

• Second row center is, of course, Sam's troll song, which he graciously bestows on Frodo, Merry, Pippin, and Strider; within that song, Tom and the troll tutoyer each other as noted.  
• Lower left is when Aragorn regales Gimli and Legolas with a nifty history lesson before they venture out to the Paths of the Dead; Isildur tutoyers the faithless king and his people with a curse.  
• Lower right is the elvish song of the ents and entwives, sung by Treebeard for the edification of Merry and Pippin. 

Fig. 2: Tutoyering in Story and Song

Tolkien, J. R. R.  The Lord of the Rings.  2nd ed. 1966.  50th Anniversary One-Volume Edition, HarperCollinsPublishers, 2005.  Quotation is from book V, chapter 6, third unnumbered section, paragraphs 9-12.