It's my first time flying to Guangzhou, China (the first time I went to China was the time I flew to HK and then went to Shenzhen)

The main purpose of me going there is to find some relatives that I have only met them once in Shenzhen, and I intend to visit my grandfather's "kampung" and their respective tombs...

I've got my Visa, and i'm flying with Tiger Airlines from Changi, Singapore... While my other relatives are flying from KLIA (Airasia)

Arrival time is 15 min later than the 5 other relatives flying with AirAsia...

After that, I will fly back from Shenzhen by Airasia to KL then take another Airasia back to Singapore... arrival 1515, departure for the next plane is 1730, enough time to check in rite?

Baiyun is a pretty new airport, and it will cost around 150 RMB to 200 RMB to take cab from airport to city. I don't know about other public transport rate, last time I went there was back in 2008.

2 hours and 15 minutes, you might spent 1 hour to retrieve your luggage (usually won't be so long), and left you have 30 minutes to check in only. And Air Asia now starting to charge for counter check-in, I guess you can do web check-in first in ShenZhen.