Is it safe to single stake them?

I have been using the wolf fangs for years now they work a lot better for me.

Only with cable or chain stakes.
I have read about a few that used a 30 inch rebar stake with a wing Welded to it 6 inches from the bottom.

Not recommended.

That said some guys do it.

I have had to many coyotes jack a single stake out. Everything gets double staked or earth anchors now.

X2

Iowa earth anchor..

Angled pipe anchors, like ones mentioned above

With rebar not advised... I double stake with 1/2"×24" rebar.

I’ve run the gamut here for over 40 years and used about all. It’s really what your predominate soil type is. I mostly use Wolf Fangs when I stake and many are about unretrievable with out a lot of hard digging. Some can be pulled with a little digging. Some bend trying to pull. I have areas on strip pits a single 15 inch 3/8 stake would hold anything. Before earth anchors I cross staked a lot. Now, I’m really on a kick using drags. Once you get over the fear of it it’s sure nice just picking the rig up when pulling.

If you have trouble with coyotes jacking re bar stakes. All you have to do Is have a washer on both sides of your stake swivel. This doesn't allow the swivel to drop down on the stake and get a new bite. For the most part this will stop most stake jacking.
Long chains will also limit stake jacking to some degree.

I use wolf fang anchors and if I'm a bit wary of the ground I'm working In I will use 2 and cross stake.

KYTrapper2005 I live maybe 20 miles from you - go with some type of earth anchor. I use Wolf Fangs as they aren't that expensive (I buy them in big lots to keep the price down) and I make my own cable stakes. Even with a good cable stake puller you will lose a bunch. The rocky soil here makes retrieval hard. If that wolf fang gets wedged between a couple rocks it isn't coming out. I just cut the cable when that happens. Trying to drive 2 rebar stakes here is a pain and your stakes look like pretzels real quick. Be sure to get a good quality driver for the cable stakes or you will destroy it in a day.

When I trapped the desert before the disposable stake days, I used a single 24” rebar stake. Had one jacked about half way once but never lost a coyote. At times I wouldn’t set a place because the ground wasn’t suitable for a stake. At times I could get away with tying off to a big sage. What REALLY helps prevent jacking is a long chain. I’ve never run less than 24 inches and use 60 inches exclusively now. No pull outs and no difference in foot damage.