_{Note: The introductory text is only for flavour. All information needed to solve the puzzle is in the images below. Feel free to skip ahead to where it says "puzzle starts here".}

Prologue

It was a tense time in Jafe Q. Puzzlesmith's office. All his new puzzles kept falling short. People were simply too clever for his usual tricks. The last one had just been solved in ten minutes sharp. To add insult to injury, while driving to work that morning he had just –

You know what, this was exactly the problem. Immediately he could hear the wheels turning in readers' heads. Falling flat? Ten minutes flat? Flat tyre? People had learned to catch these subtle clues so effortlessly. From the moment he mentioned "Q" as his middle initial, someone was probably already keeping track of whether he was using every letter of the alphabet in the text.

That's it, he thought. No more clues like "which traffic sign is red" or "how many bits are in a byte". Or "how many brains a person has", for crying out loud. It was time to bring out the obscure stuff. Muahahahaha!

Determined, he walked into the room holding his dead tree collection and started working on a new puzzle.

Puzzle starts here

Clue 1

Clue 2

Clue 3

The final answer is a mythological creature.

Hint:

Each clue has a separate answer. Put together, they point to the final answer.

Erratum for clue 1:

I seem to have confused two characters that look a bit alike: ⾟ and 𦍒. My bad!

The solution is

PHOENIX

Clue 1

Combining the missing radicals ⺅,尹, ⻌, and 𦍒 (Thanks @Hugh) yields 伊達, a Japanese surname pronounced DATE.

Clue 2

Thanks to @Chrone and @AHKieran, the shorthand reads between the wrist and the fingers, or PALM.

Clue 3

Thanks to @Bass, we know the key word is something between "George, Laura, Barbara and Jenna" and a "Psittacus Erithacus". The first is the Bush family, and the second is a species of parrot (Grey Parrot). GENUS falls between family and species in the classification of an organism.

Final

Combining the 3 keywords result in DATE PALM GENUS.


Date palms are part of the PHOENIX genus. A Phoenix is a mythical creature that is basically an immortal fire-bird thing.

Partial answer for part 3:

The text in the image is

phonetically written English written from right to left, and reads like this:

 An example of X is George, Laura, Barbara and Jenna

 An example of Z is Psittacus Erithacus

 What is between X and Z?

Solving for X and Z, we get

X = Bushes, Z = Parrot (or maybe just "Bird")

and then, something along the lines of

A bird in hand is worth two in the bush

Part 2 looks like

some kind of shorthand, possibly Gregg, but since I know nothing of stenography, I have no idea, really.


In the comments, @Chrone confirms that it is, indeed, Gregg, and it reads: "between the rest and the fingers".

This could point to "hand", which is also a word between bush and bird in the proverb possibly suggested above.

Part 1 seems to be a list of

Japanese cities

but I've yet no idea what to do with it. For starters,

acrostically, they read "DID YOU THINK IT'D BE THAT EASY", which is obviously a red herring.

Although my 日本語 is a bit rusty,

the middle character in "Dazaifu" seems very unusual for a kanji. Indeed, it should be 太宰府. Time to check the spelling on the other cities..


Higashiōmi should be 東近江

Usa should be 宇佐

Kimitsu should be 君津

Answer:

The word: SELKIES

Clue 3:

Taking Clue 3 and reading it in reverse, converting the symbols to similar ones in the Latin alphabet and configuring to actual words it reads:
an example of X is George, Laura, Barbara and Jenna
an example of Z is psittacus erithacus
what is between X and Z?
psittacus erithacus is a Grey Parrot (thanks @Timoris).

The names for X are the names of famous Bush's (Thanks @Bass)

The question then ask "What is between Bush and (Grey) Parrot?"

The Bushes are all from the US, and the Grey Parrot is from Africa. Between the US and Africa lies the Atlantic OCEAN.

Clue 2:

As identified by @Bass, this looks like Gregg shorthand, using the guide below I think it says something like:
Between the wrist and the fingers

(Thank you @Chrone and @Timoris for seeing that)

Which would then point to HAND or PALM.

Clue 1:

Is a list of Japanese Cities. (with apparent misspellings but unknown answer)

Finally:

OP has included that all 3 clues point towards a mythological creature, so far I have deduced that it is Ocean dwelling and something to do with a hand/palm. Well Selkies are Ocean dwelling seals that can turn into humans who have hands on land??? so lets go with that for now.

Partial Answer

Part 1 — Japanese Cities

It's easy (if you read Japanese) to notice that...

some of the names of the cities are spelt incorrectly. For example,


— The correct rendition of Usa is 宇佐, but the table above is missing the radical ⺅, called the ninnben (にんべん). It is the radical version of "human" (人).

— The correct rendition of Kimitsu is 君津, the table above is missing a portion of 君.

— The correct rendition of Dazaifu is 太宰府, t̶h̶e̶ ̶t̶a̶b̶l̶e̶ ̶a̶b̶o̶v̶e̶ ̶i̶s̶ ̶m̶i̶s̶s̶i̶n̶g̶ ̶"̶⾟"̶,̶ ̶m̶e̶a̶n̶i̶n̶g̶ ̶"̶s̶p̶i̶c̶y̶"̶. Sounds like there was an error in the puzzle, the correct glyph is 𦍒... which funnily enough is not a Japanese kanji but instead a Chinese one. I'll look into it.

— The correct rendition of Higashiomi is 東近江, but the table above is missing the radical ⻌, called the shinnniyou (しんにょう), typically relating to movement.


These are the ones I recognized off the top of my head. There may be others.


I thought that there may be a kanji that combines these missing parts, but no kanji exists that uses both the にんべん and the しんにょう.