Trekmania is owned by Dafedz, so getting permission to use his writeups won't be difficult - assuming we can contact him in the first place. He seems to have gone AWOL lately.
I could write up a list of information on the planet types without this information anyways. I've already written info on the star types based on other sources such as Memory Alpha, and I could do planet writeups from a very useful site that I found
The page you've linked to actually explains a little mystery for me as well. I've got a load of animations of rotating planets of varying quality on my computer, and i'd forgotten where I acquired them from. One of them is an animation of the last planet on that page. I must've got them from Dafedz.
