Is the AlphaESS SMILE-G3-T5 compatible with the AlphaESS Integrated CTs (no external meter)?

Yes — listed by the manufacturer.

The manufacturer's published pairing data lists these together.

Manufacturer's compatibility listListed together in the manufacturer's published pairing data. A cited document reference is being added as datasheets are processed.

Pairing details

CT specification
cts: Integrated CTs (built into inverter) · note: No external meter required for basic operation, but RS485 meter recommended for reliability · type: Integrated · cableLength: 10m · maxExtension: For best peace of mind, use external meter via RS485 (up to 1000m with good workmanship)

Both products

Design a system with this pair