Emptiness means that all things are empty of their apparent nature (i.e. all attributes are mind-created) and self-existence. Not that they don't exist. AFAIK, Buddhists also do not concern themselves with subjective / objective classification of reality.

Nagarjuna’s critique of the notion of svabhāva (Mmk. ch.15) argues that anything which arises according to conditions, as all phenomena do, can have no inherent existence/nature; for what it is depends on what conditions it. (source)

Kabbalistic Ayin is roughly equivalent with Buddhist "formless realm", particularly "sphere of nothingness". Nothingness, however, does not mean non-existence. Only absence of forms. Brahman, Tao, etc. are "beyond" Ayin / Ein Sof. This is basically the greatest mistake in Judaic thought and it makes the whole Abrahamic tradition inevitably dualistic. No wonder there is that famous scene in NT John 8:58-59 (and no, the guy didn't claim that he is sole God, though he surely claimed he is God).