Until this issue is addressed, if you run your package from a binlink it's dependencies will NOT be in its path unfortunately:
For now, instead of using a binlink create a script like this for running your packaged command:
#!/bin/bash
exec hab pkg exec your/pkg yourcmd $@
When you run your command via hab pkg exec, the commands exposed by all it's dependencies will automatically be in its PATH without needing to be binlinked. You only want to use binlinks to expose commands to a user in their normal shell, not for fulfilling dependencies between packages