This is listed by Wikipedia as a "common" type of wave:
Another common wave is to raise one's hand and repeatedly move the fingers downward toward the palm.
Wikipedia also seems to suggest that this style of wave originated in Europe:
Waving the hand to say "hello" or "goodbye" [in Europe] is done by moving the fingers down ...
In "Deer God" (season 1 episode 5) it is revealed she is a Lt Col Ret.
Note that the subtitles in the screenshot are actually incomplete. What she actually says is:
I'm the retired Lt. Col. you had on the horn this morning.
See also this fan transcript.
This was likely not a shrewd political maneuver, rather simply a change of heart.
Bullock doesn't immediately go to Crook after visiting Dan. He first speaks with his partner Sol Star, and the two have the following exchange:
Star: I'm sensing you've done things today you wish you could amend, Seth.
Bullock: What kind of man have I become, Sol?
Star: I don'...
Visting my grandparents, I slept in three different bedrooms in their house during different visits, and two of those bedrooms had two beds even though I was the only one sleeping in those rooms when I visited. Over the decades, I slept in about five or six different bedrooms in my family's vacation home, and at least two of them had two beds when I slept ...
How does "the gimp" come to be in Maynard & Zed's basement?
According to Quentin Tarantino (Pulp Fiction director) in an article published by Empire Magazine — EMPIRE 30: Quentin Tarantino Answers Your Questions, where he answered a similar fan question (emphasis mine):
Question: What is the Gimp’s backstory in Pulp Fiction, and what happened ...