which is the best option to travel from Guiyang Airport to Guizhou Minzu University?

You can take the Shuttle Bus Line 5 from the airport to Kong Xuetang and then walk south about 8 minutes, you can get to the university. From the arrival hall, you can follow the signs in the airport to buy bus tickets and board the bus.

Thank you. Do you know how much it will cost? And whether it will still operate on 6.00 P.M?

It costs CNY20 and operates until 19:00.

Thank you. Do you happen to know if there is any WIFi counter on Guiyang Airport? Or if I can use the WiFi without Chinese phone number.

As I know, there is no Wifi counter in the airport and you can ask help for the airport staff.

Uh oh. Does that mean I have to obtain a Chinese number in order to be able to use the WiFi?

Well, there are two ways to connect the Wifi.
One way needs your Chinese phone number.
The other way needs wechat number.

Thanks man. It will work even though my WeChat number is Indonesian one right?

Also, if I choose to take taxi, do you know whether they have a counter or I will have to call the driver myself? I don't want to be scammed, so preferably there is a taxi counter.

Yes, as I know, only if you have a Wechat number.
You have to go to the official taxi stands at the airport in order to find regular taxis. The boarding site is outside the 1F, Terminal 2. You can easily find the place according to the English signs at the airport.
Hope helpful!

Thanks man. Last question, do you know the taxi fare? is it exactly the same as the one shown in this post?

If you wanna take a taxi from the airport to Minzu University directly, the cab fare is CNY 60-70.

Thank you Phil. I really appreciate your help.