Access KAwachi Wisteria Garden via JR Yahata?

Hi there,

Yes, you should be to get there with this pass.

Note that you can't use the Shinkansen but should be good using the JR Kagoshima line up from Hakata station.

thank you!

by the way, I got below fr Hyperdia:
FR HAKATA through SHINKANSEN SAKURA 546
TO KOKURA JR Kagoshima Line Rapid for KURUME
end YAHATA. I ride bus after and walk rest of the way to reach Wisteria GArden.
Is above HAkata to YAHATA trip covered by JR PAss ?

No, as said above, the Shinkansen is not covered but you can use the JR Kagoshima line instead.

When using Hyperdia, remove the Shinkansen options and you should get the correct lines.