Can I play a unit in banish from Cursed Sarcophagus with shadow clone?

No. Cursed Sarcophagus can only play units banished by its own play trigger ("When you play this, banish all units from your trash"). A unit banished by the Shadow Clone token's attack trigger was banished by the token's effect, so Cursed Sarcophagus's "[T]: Play a unit banished with this" cannot access it.

Banishment tracking is strictly per-object: each effect can only reference cards banished by its own linked abilities (Rule 427.3.a, Rule 397). Same principle as two different banishing cards never sharing their banished pools — the token and the gear are separate sources, so their banished units are separate pools.