If I buy ROSE on Binance, am I good to add the Emerald straight to Metamask and send it there?
You can't transfer directly from CEX to Emerald. First you need to send to the wallet extension, as extension wallet is native so you can withdraw and deposit to CEX. From there you can send funds to your metamask wallet to use on Emerald. Or you can bridge directly into metamask from other networks, but as we saw earlier, not all pairs are supported. Here is also a step by step tutorial that you can use https://docs.oasis.io/general/manage-tokens/how-to-transfer-rose-into-paratime/