Lightning is layer two as can be settled onchain directly.

Custodial ledgers and ecash mints are equivalent in the sense that there is no direct (meaning trustles) settlement to chain or LN.

They can be viewed as an alternative closed system or maybe as layer 3 (for the trusted conversion) depending on the definition.

By this view a mint or custodial LN wallet supports the base layer or LN only on the level of the custodian. The users transact intraledger and can swap out in a trusted fashion.