not before ADA : )
ADA will be added but it will take alot of time and engineering since ADA is on it's own chain, I would estimate that between the 5 coins coinbase said it would list (ZRX, BAT, XLM ZEC and ADA)
that ADA would be last among them.
It will probably go like this
1.ZRX
2.BAT
3.Zcash
4/5. XLM or ADA
The team (IOHK) has been working on this integration since Ethereum classic was listed on the coinbase. They work for both. Although it actually looks much more practical and quick to list BAT, as it is an ERC-20 token, there are other issues involved related to volume and importance to the market.
I think XML, ADA and Zcash will be listed the same week sometime in November.