[thaumasiotes]

> published by G?rge Allen

Obviously, it says George.

(Knowing what an inscription means is actually an important real-world method of being able to read it!)

The "Z" used by Tolkien there appears to be his own invention. The whole inscription is something of a mess; a few things are put into runes by sound, but mostly a fairly strict letter-to-letter transcription is used. This is especially bad in "published", which prints an "S" followed by an "H", reflecting nothing about the actual word. (The sound in question would, in a real Anglo-Saxon text, be represented sc, not sh; Tolkien in his other documents used a mirror-reversed S rune instead.)

[ben_w]

It's also the only time he used that for "e" on that page, everywhere else on that page has "ᛖ" (ehwaz).

Quite plausibly because, as you say, it's somewhat phonetic, given that's a silent "e".

And yes, it is indeed a mess, the futhark I learned had only "ᚲ" for both "c" and "k", while that text has a different symbol for each in "back".

[thaumasiotes]

> It's also the only time he used that for "e" on that page, everywhere else on that page has "ᛖ" (ehwaz).

He isn't using it for "e". He's using it for "eo".