That lab seems to take a high road when they are both vying for the stick. Very playful and comfortable backing off until the opportune moment. I might, in my uneducated mind, be careful with guarding objects around other dogs. Some understand the signal, others not so much. By no means am I claiming that Kira has a problem with resource guarding - I am just saying that with another less playful dog who is more assertive (and they both try to establish rank by controlling resources) you might have a scuffle on your hands.
As far as Kira's behavior, she didn't look spooked or flighty (which you said was the cause of the original attacks on her) but I would have loved to see the initial reaction and introduction - would tell more about her than how she is here. She looked pretty comfortable having another dog around in that video.