No, staking is only available on Ethereum mainnet. If you want to test this you can test on a fork network using tools such as [Aave Sandbox](https://github.com/aave/aave-sandbox).

According to the [aave docs](https://docs.aave.com/developers/v/2.0/protocol-governance/staking-aave) at the moment the Aave Stake contracts (from V2 of Aave) are only available on Mainnet & Kovan at the moment. That being said, you could always deploy the contracts on goerli yourself, or test them out locally.

I don't think so. If any, I'm interested !