Any pass should I buy if I go to Koyansan

1) I already bought the 4 days Kansai wide pass and would like going to Koyansan from Wakayama, what other pass I should buy or pay individual charges is more saving.
Or skip to use the Kansai wide pass, just buy other pass for the trip from Wakayama to Koyansan.
2) How to reserve the seat of the sky train to Koyansan as I know there is an email to reserve seat through English Language but I don't exactly know the email address. (Also how to pay in a secure way.

Thanks !!!

I already bought the 4 days Kansai wide pass and would like going to Koyansan from Wakayama, what other pass I should buy or pay individual charges is more saving.

The Kansai Wide Pass is not very convenient for accessing Koyasan, as it does not cover the Nankai Railway. By JR you can only get as far as Hashimoto Station, and that is usually a detour unless you are coming from the Nara or Wakayama City area.

For Koyasan alone, the Kansai Wide Pass certainly makes no sense. But I assume you would use it for other trips, as well... It is difficult to judge without knowing the context of your Koyasan trip.

Or skip to use the Kansai wide pass, just buy other pass for the trip from Wakayama to Koyansan.

If you come from Kyoto or Osaka, then Nankai Railway provides the easiest access to Koyasan, and the Koyasan World Heritage Ticket is usually a good deal:
http://www.japan-guide.com/e/e4904.html

How to reserve the seat of the sky train to Koyansan

Sky train? Do you mean the cablecar? Seat reservations are not possible for the cablecar! Nor are they possible for the Nankai Railway trains except for the limited express trains for which seat reservations are mandatory.

JR and Koyasan is not good combination.

Whether you should buy JR Kansai Wide Pass depends on the other places you plan to visit.

If you have the JR Pass and plan to travel from Wakayama, catch the train on JR Wakayama line from Wakayama to Hashimoto where the JR Line meets Nankai Railway line. no pass needed in that case.
http://www.japan-guide.com/e/e4904.html

http://en.wikipedia.org/wiki/Wakayama_Line

Some of trains of JR Wakayama line stop at Kokawa station (halfway station to Hashimoto). You may be unable to go to Hashimoto directly.
It is the one of the most un-convenience railway I know.

Is the train from HASHIMOTO to GOKURAKUBASHI need reservation for the seats of better scenic view and how can I make the reservation in English (through travel agent of Nankai)

Is the Koyansan world heritage pass cover my trip from Wakayama to Koyansan or I need to pay between Wakayama to HASHIMOTO.

Nankai Railway sells Koyasan World Heritage Pass.

Wakayama line from Wakayama to Hashimoto belongs to JR.

You can not ride JR train with Koyasan World Heritage Pass sold by Nankai.

One way fare from Wakayama to Hashimoto is 820yen.

Is the train from HASHIMOTO to GOKURAKUBASHI need reservation for the seats of better scenic view

Again: none of the trains have unreserved seats, except the limited express trains for which seat reservations are mandatory.

and how can I make the reservation in English (through travel agent of Nankai)

At the ticket window of Nankai Railway stations. The person at the ticket window is unlikely to speak good English, but enough to make seat reservation.

Is the Koyansan world heritage pass cover my trip from Wakayama to Koyansan

No. Here are the basics about the pass:
http://www.japan-guide.com/e/e2358_012.html