So now they're best buddies?
We're getting there. They play very rough, and someone is always letting out a yelp, it seems. When they are out of control, one or both of them get sent to their crate(s) for a few minutes. But so far, no blood has been spilled, and no one is missing any body parts.

Our dog trainer said to separate them when their playing gets to be too intense to give them a couple of minutes to calm themselves. They are getting better at self-regulating their play (automatically stopping or running to get a drink of water), but they've still got a way to go before they're BFFs.
I posted their bully stick photo on a whippet website I post at, and people were amazed that they were sharing food. The comments were along the lines of "My dogs would never share food. No way."
I hope I'm not jinxing myself here, but I think Forest is the best thing that ever happened to Ember. She is eating better -- finishing all of her food -- and she seems much happier. Plus, she is much more outgoing when we have visitors. I am so thankful that Ember's breeder gave Forest to us.