"Life Below Zero" uses actors?
Well, in the sense that these people who are essentially living a "subsistence" lifestyle — to one degree or another — in Alaska, were "recruited" for this series, and are surely paid, yes.
As Sue put it in a Chicago Tribune interview, May 29, 2013: (click →)
"Chicago native Susan Aikens stars on NatGeo's 'Life Below Zero'", quoted here in part:
Q: How did you come to be a TV star?
A: At this point, I don't see myself as a TV star, but thank you for the compliment. I was approached. People came out. One of them I knew from being on a different show. And they talked to me and they wanted to see what I did and how I did it. I like my privacy, but I don't mind sharing it as long as it's tastefully done. From what I have seen, some reality shows appear that they force a dangerous situation, or they have you say something totally ridiculous that you'd never say even if you got paid to. This show, I found, I have respect for because it showed what I was actually doing. I smoke cigars, I've been known to swill a single-malt Scotch, and I swear a lot. And they didn't try to change that. It was 90 below zero, 90-mile-an-hour winds, and I'm out there laughing and doing my (stuff)."
And also, from this (click →)
Joe Rogan Experience #566 - Sue Aikens interview (YouTube video, 1 hr. + 24 min.), quoted here in part:
Rogan: "What led you to this spot?"
Sue: "In pre-school, in kindergarten … when they ask you 'What do you want to be when you grow up?' … for me it was ah… lighthouse keeper… ".
[FRN: Funny, I have always thought that if she was in da UP in the late 1800s/early 1900s, she would probably be a lighthouse keeper, say at Gull Rock, Manitou Island, Stannard Rock, or Huron Island, Granite Island, … all very remote & isolated.

]
In this
unscripted Joe Rogan interview, Sue comes off as quite well educated and well spoken, with just a tad of that wry sense of humor that I enjoy.
Are these Life Below Zero episodes scripted?
Another quote from Sue that I encountered somewhere today (and since misplaced the source):
Sue: "It's in my contract, I don't do scripted anything."
That figures, sure sounds like Sue!
In any event, I enjoy
Life Below Zero, The Last Alaskans and such 'cuz my grandparents and uncles lived such a hardscrabble "subsistence" lifestyle in da UP from the early 1900s, and I witnessed much of it as a kid in the 1940s/1950s: the deer/small game hunting, the trapping, "making wood" for the wood stove (for both heat and cooking!), so it's a bit of a flashback to my own family's experiences.
Incidentally,
Erik Salitan is the one I have the most respect for, for his disdain for power tools (chain saws, snowmobiles things that can break down at the most inconvenient times) in preference to old fashioned hand tools (axes, knives) and ingenuity. Just like life back on the family farm in the early days!