Definitely getting Minnying vibes! “The mourning glade” was the plot of that particular poem.
Also posting this in text form, because it seems important:
The acoded note Owl brought to Toad:
1 – WITEBKINGIGREDIENT
10 – NHNNONRTHNINENSION
14# – THRONEYTHRAIDTHRORTHRTHRERVICE
15# – WNEHREPEATEDACMLAINGERPXESSION
18 – ROUSONFOUACOUDSOUAT
20 – THEILETTERIIAFTERIIIRIVANDVALSOVIBEFOREVIITVIII
28 – EANTSEFTEREEOLIDAYEEAL
32 – HETOUNDTTORSETAKEST
15 Calming? Shh maybe
32 Could be… The Sound A horse makes?
I think you’re on to something there, @Robert, on #15. To me, it looks it could be the words “When repeated a calming expression,” with some scrambling about.
14 replace thr with a letter. Money paid for a service
Fee?
28 - looks like there are E’s in place of the first letter in each word: “PANTS AFTER A HOLIDAY MEAL”?
Also, any guesses as to why only two have pound signs?
So we have - possibly:
1- White baking ingredient
Answer: Flour
10 - The fourth dimension
Answer: Time
14# - Money paid for a service
Answer: Fee
15# - When repeated a calming expression
Answer: Shhh
18 - Reason for a cold sweat
Answer: Fear
20 - The letter after R and before T
Answer: S
28 - PANTS AFTER A HOLIDAY MEAL
Answer: Tight
32 - The Sound A horse makes?
Answer: Neigh
18 – ROUSONFOUACOUDSOUAT
I dunno if this means anything but…FOUACOUD kinda looks similar to Rochefoucauld to me? Probably not the right track, but thought I’d mention it.
As @Sellalellen stated earlier, 20 is “The letter after R and before T”, which would be “S.”
Whoops, I totally missed that one! It’s added now. Thanks guys! 
18… Our son of
Since it looks like there are multiple things going on here, I just want to make a list of all the things used to unravel this in case they become important somehow:
Each line has a number label, two with pound signs (or hashtags for the Internet generations.)
Each line has a clue that seems to suggest a specific word: “flour,” “fee,” etc.
Each line has a particular method of making the clue somewhat illegible: in 1 the second letter in each word is removed, in 20 they’re separated by Roman numerals.
Maybe most of this is unimportant, but I like record keeping. 
10 seems to have n as a placeholder. And 18 looks like it’s jumbled?
New theory on 18: replacing “OU” with two other letters could give “Reason For A C_ d S _at”?
Edit: Or replacing O or U, but not both?
18 has a lot of ‘ou’. That could be the word divider
Hmmmm. Lots of single letters or pairs of consonants.
After a holiday meal… I’m guessing it would be some kind of loose pants, maybe joggers? Pleats?
10 the fourth dimrnsion… if you kinda squint
With 32, could the line “Barring Fours from thirty-two” be important…I’m working on this right now.
That makes perfect sense
I’m not convinced that’s correct