To have ambient occlusion with yafray with HDRI lighting and bump mapping (that you can see cuz ambient occlusion does not work well with bump mapping ) ? or would you render them separately and then composite them ( and if you do? do you composite with blender or different program? or does it matter?) cuz if you can do all that with blender then that’s awesome!
AFAIK, all three things are possible together, I mean, ambient occlusion with HDRI lighting and bump mapping in yafray.
Just be sure that ‘no bump’ is disabled if you use irradiance cache.
When this button is disabled, the irradiace map will take into account also surface changes derived from the bump map. Since irrandiance cache tends to sample more points in areas with changes, this can complicate the irradiance cache quite a lot with complex bump mapping. When ‘no bump’ is enabled, the irrandiance cache will only take into account scene geometry, and therefore there won’t be shadows from indirect lighting that should be derived from the bump map, but shadows for direct lighting will remain, also indirect lighting using scene geometry.