Well I found my answer. The Onfair models do in fact lean back at a potentially hazardous level. In the event of sudden acceleration, or god forbid, a rear end collision, your neck will no doubt suffer damage. The travel is far more than stock.
Although I asked onfair about this before the purchase, they never responded. Should have been a clue. After the purchase Onfair's service turns into mush. Once they have the $$, don't plan on getting *any* useful responses from them ever again. On top of that, despite the 9" models not fitting the vehicle properly, not opening properly, and basically acting adverse to everything they advertise about them, they refuse to exchange or refund in any capacity.
My best advice, if you want to deal with a quality merchant, DO NOT DEAL WITH ONFAIR. You can buy these cheap Chinese headrests at various other places online for cheaper, and since you don't get service from onfair anyways, there's no point in the "illusion" of buying from a company who will help out locally, because Onfair does no such thing.