Yes

Because a taxi only costs krw 3300 (from the nearest subway station) and you do not need to wait for the bus and it takes you door to door unlike the bus. If you are a small group the difference in price is even smaller. The choice is of course yours :)

Maybe worth taking a subway to the stop then taxi from there so less exp? I have only been with subway and bus so don't know how much it would be.

Yes there is a climb from the bus and make sure you have clear directions so you do not take the road to the right and miss the entire temple area.

I don’t know, I am sorry

Hi, I'm not really sure if they're open during Chuseok, you may try to call 1330 from Skype it's free of charge. I've called from Indonesia and it's work well.

I stayed in BIFF Square area. From there take a taxi to the temple is approx less than an hour. Can't remember exact timing. More than 30mins but less than an hour. Depending on how you intend to explore the temple, it can take anything from an hour to two. As when you get out of the temple, there are some forestation that you can explore. There is a stream that runs through which is quite picturistique. Then give it another hour to travel back to station. This is if you prefer to explore the temple at a relaxed pace. Can consider having lunch at the Busan train station area. Loads of food there.