My Take on the Exorcist Symbols From Zodiac Excorcist Letter and Cycled Letters From the 340
Lets break down what they could mean, first breaking down what they generally look like.

If we break down what these symbols look like on the surface I come up with the following:
JK
J (Backward K)
F
N???
JKFN
JKPFN
JKPFV (Assuming that last symbol is an upside down “V”)
All together: JKPFVN
Those are the letters that I see.
That last symbol at the end looks like one of the symbols in the cycling in “Lets Crack Zodiac” video on the odds and ends.

Notice how in the cycled letters we see the “J”.
Next set of cycled letters we see the upside down “V” looking symbol. This breaks to “O”.
Lets see what these cycled letters break to:
J = A
M =O
Upside down “V” = O
Half filled box = A
V = O
All A’s and O’s.
Going back to the Exorcist letter what I believe all the letters are as follows:
JKPFN
If we break these letters and translate them using the 340 Key we get:
“J” = Either A or S from what I see
Backward “K” I
P (Filled P) = S
F = F
N = E
So if we translate that symbol using the 340 key I got:
AISFE
SISFE
Doesn’t look like anything significant to me. Perhaps we should take those symbols as is, I don’t know if translating them using the 340 key produces anything significant.
Below is my opinion:
The symbol and without interpretation is to be taken as is, meaning no use of any key or anything to interpret this as my take is that the symbols to me look like either
JKPFN
JKPFV
I think it means and stands for JOSEPH PAUL FRANKLIN but that is my take. Taken along with the “tit willo” three times we see three times the number 8 inside the words tit willo.
The correct spelling seems to be “TIT-WILLOW” not tit willo.
Ref: https://opera-guide.ch/highlights/show_highlight.php?id=2884&oper_id=528&uilang=en
The letters A and O seem to be of some importance I think. The backward “L” symbol is also repeated in the 408 key and 340 key. This A is also used twice in the Z13. I think there is soemthing to the link between the “L” or what I think is a variation of the letter “J” and the letter “A”.
Lets Crack Zodiac Episode 9 Odds and Ends: https://www.youtube.com/watch?v=ByMe8D9sxo4&t=667s
Exorcist Letter: https://www.zodiacciphers.com/the-exorcist-letter.html