JR pass

i am going to get a 14 days JR pass (covered whole Japan). Just wondering whether the pass will cover the trip from Osaka station to Kinosaki onsen station? also does the pass covers the JR bus service from　JR武雄温泉（JRバス30分）→嬉野温泉?

and lastly, can i use the JR pass to exchange a bus ticket for the あそゆふ高原バス that travels from Yufuin to Aso station.....?? i am very confused...........and don't know who to contact for solution/?????!!!!! thanks

Just wondering whether the pass will cover the trip from Osaka station to Kinosaki onsen station?

Yes:
http://www.japan-guide.com/e/e3526.html?aFROM=2157_3525

also does the pass covers the JR bus service from　JR武雄温泉（JRバス30分）→嬉野温泉?

Yes! It is a local bus operated by JR.

can i use the JR pass to exchange a bus ticket for the あそゆふ高原バス that travels from Yufuin to Aso station.....??

No. The bus is not operated by JR.

About the Japan Rail Pass:
http://www.japan-guide.com/e/e2361.html

can i use the JR pass to exchange a bus ticket for the あそゆふ高原バス that travels from Yufuin to Aso station.....??

No. The bus is not operated by JR.

The bus below (see link)is run by JR Kyushu, is that mean i can exchange bus ticket for free?
http://www.jrkyushu.co.jp/tabi/yamanami/index.jsp

I think this is a sightseeing bus. I doubt that the Japan Rail Pass is valid, but I am not 100% sure.