It looks to me like ANT_STACK_CONFIG is redundant in SDK 14.0.
nrf_sdh_ant_enable does all the same setup plus, it looks after all the new softdevice handler stuff.
I think ANT_STACK_CONFIG should be removed of marked as deprecated.
Thoughts?
EDIT 9 Oct 2017
Ant stack config can be found in NordicSDK14.0\components\ant\ant_stack_config\ant_stack_config.c
nrf_sdh_ant_enable can be found in NordicSDK14.0\components\softdevice\common\nrf_sdh_ant.c