We don't know how long it took for the girl who ate her mother to turn, as we don't know how long she'd been "dead" before she turned. So, we can't say she died instantly here.

Her mother turned rather quickly, but not instantly. I'd say she most certainly died almost instantly after having the arteries in her neck ripped out. It was a couple of minutes before she turned.

By airplane guy, if you mean Chris' mercy kill? He didn't turn... Chris hit him with the blunt object and the hit didn't kill the man. He gurgled a bit, revealing that he was still alive; Chris then bashed his head in some more, ensuring that he succeeding in killing him.

In the Walking Dead, many people turn right after dying as well. It's usually within a few short minutes.

 

I think the better question is "where are the fast / smart zombies". If you remember in season 1 of TWD - some of the zombies could run, climb fences, find their way home, turn doorknobs, bang on store windows, hold teddy bears, etc..... It wasn't until later (The departure of Darabont) that they became slow stupid shamblers. This was explained as an effect of time. These zombies are "fresh" - they should be fast and smart - remember, Rick is still in a coma. So what the people in FTWD should be encountering are "fresh" season 1 smart zombies like Morgan's wife, the teddy bear girl, and the bunch that came after Rick and Glenn....

 

Possible answers to the OP question

1. we got more bounce https://www.youtube.com/watch?v=Q8dAfxBXVgU

2. many Californians already brain dead so turn is quicker

 

That was more of a (very poor excuse). TWD earlier zombies' behavior was an inaccurate representation of zombies in Kirkman's universe. They fixed their mistake and clearly didn't want to repeat it.

For example, years into FTW's ZA, people who get bitten or die and turn don't turn into smart zombies. They're the stupid ones. One example of why their excuse still simply doesn't make sense.