At the map at the official website of Garajonay, Agando just seems to fit into the park borders:

http://reddeparquesnacionales.mma.es/en/parques/garajonay/guia_mapa.htm

I Had a look at the Google Earth Protected areas map
http://www.unep-wcmc.org/kml-file-of-world-heritage-sites_812.html

It shows one side only of Agando as being inside the NP!! The Northern side facing the road!! This mirrors the map you cite above. The other 2 Roques are defnitely shown inside. I can see no indication of any "extension" having taken place but the status of the Roques does appear to have been changed over the years and Garajonay was quite an early inscription.

(4746) Canals
Luebeck - Elbe Canal
>> I don't believe it's within the inscribed zone

Art from unconventional materials - Jungfrau - ice
Wieliczka - salt
Hallstatt - human bones
>> too trivial for me (although I was the one who originally suggested it, years ago), also hard to define

Named after the colour of their rocks:
Uluru - dubbed the Big Red Rock
Petra - dubbed the Red Rock
Quebrada - featured the Hill of the Seven Colours
>> too trivial, locally there will always be a name like this for a specific mountain or a rock (and Petra is not commonly called the Red Rock, rose-red city is the only reference I have come across)

Greater Blue Mountains
I posted both "Botanic Gardens" and "Sundials" some time back. But I'm pretty sure now that the Blue Mountains Botanic Garden is not within the inscribed area.