Here's what I think the full class list looks like:
Notes:
1) The list is sorted by surnames, in hiragana order (a,i,u,e,o,k,g,s,z,t,d,n,h,b,m,y,r,w).
First half of the list (1-15) - male students' names; second half (16-30) - female students' names.
2) All the names come from the seating chart posted earlier,
Kogetsu Shirogane's post and
Japanese wiki.
3) I didn't write down all the possible readings for the given names.
Spoiler for some other stuff:
I didn't know what Kyon's number is at first but then I looked at class 1-5's original seating order and realized that everyone was sitting according to the list above when they first entered the class.
(Original seat arrangement for class 1-5)
Starting with the first column on the right, the boys - Arakawa(1), then Uematsu(2) two seats behind him, then Kakinouchi(3); Kunikida(4) and Goto(5) in the second column; (6)Sakaki, Kyon(7) and Taniguchi(8) in the third column and so on. The girls - Asakura(16) and Onoki(17) in the first column; Kenmochi(18), Saeki(19) and Sakanaka(20) in the second column; etc.
(In the Lantis video, Yoshizaki is number 14 on the list and Yamane is 15. It should be the other way around since Ya- comes before Yo-. A mistake on KyoAni's part?)
So, Kyon is number 7. By the way, Haruhi's name is the 7th one on the girl's list (7/7 = Tanabata?). And assuming that it was Tanigawa (the author of the novels) who came up with all of this, then the list also tells us one more thing - the first letter of Kyon's surname. It's either an S, Z or T; since it is between Sakaki and Taniguchi. That narrowed it down to a few hundreds possibilities alright. I just found out that Tanabata is a surname too, to my surprise.
And finally - I'm not sure if this has been mentioned before or not - the students who went to the same middle school as Haruhi are Arakawa, Uematsu, Kakinouchi, Taniguchi, Matsushiro, Suzuki, Takato, Hinata and Yanagimoto.