Did anyone 100 lbs overweight have success with toning "Bat Wings"

You can't tone extra skin like that.

You'd be unable to build enough muscle to fill it out.

Most you can hope for is not making it worse (if fat is mainly gone from there already then it may be done), and hoping for recovery of skin shrinking which can take a long time and maybe never enough to make a difference.

Resistance training is excellent anyway.
But that doesn't mean doing tricep extensions is going to help, that's usually a small muscle.
It's really going to be about the effects of a full body progressive workout - and the effects of that on helping skin anyway.
But just as you can't spot reduce - you can't make those effects pinpoint skin in certain area. Hence the slow nature of recovery.

Make sure you eat enough good fats and enough protein - fat and amino acids needed by body and cells and can always help.

I'm not going to tell you your "bat wings" will all disappear, and this is not specific to arms, but:

Part way through loss, loose skin can look worse than it will at goal weight, because there's still some squishy/loose fat conspiring with gravity to keep the area stretched out. (Fat can deplete pretty much anywhere within the fat mass, rather than shrinking neatly starting from outer cells and proceeding inward. Consequently, many of us find that an area of fat storage gets loose, squishy, soft, even floppy when some of the fat is depleted, but not all of it.)

Further, as others said, skin takes time to shrink even after the fat is depleted. Mine kept shrinking well into year 2 of maintenance, and perhaps beyond.

FWIW: I didn't lose 100 pounds, it was only 50-some. The profile photo is my arm only shortly after reaching goal, at age 60. (I had been active for some time while obese, so am not completely devoid of muscle, especially for an older woman.) Frankly, it would look less bat-wing-y in the photo if I had raised my elbow well above my shoulder, because some of the hang in the photo is still relaxed triceps. Results are individual, and genetics is a factor.

Skin is an organ. The things that keep any other organ healthy are going to keep skin healthy, too, so more likely to be elastic and shrink. That would be:

* avoiding fast loss (because it's a physical stress to lose fast),
* getting good well-rounded nutrition (macros and micros, especially but not exclusively protein),
* getting regular exercise (both cardiovascular and strength),
* managing all-source life stress,
* hydrating adequately (not crazy much, but enough),
* avoiding smoking and excessive alcohol,
* specific to skin, also avoiding tanning.

Please encourage yourself to be optimistic now. Odds are good that there will be noticeable improvement as you approach goal weight, and for some time beyond. For some actual examples of real results, take a look at before & after photos in the Success Stories part of the forum, from people who've lost similar amounts of weight. It seems like most people, when starting or part way to goal, anticipate worse loose skin than many people actually end up with in the long run. I'm not promising zero loose skin, but it may not be as severe long term as you're now thinking.

Congratulations on your weight loss success so far, and best wishes for continuing success!

P.S. I should add that many women are misidentifying relaxed triceps as fat or loose skin (every single one I've talked with about this in real life has been doing that), which is kind of a pet peeve with me. Again, not saying there's zero fat or loose skin, but it's good to understand that some of it may be muscle. I won't type out the whole "how to figure that out" thing again here, because it's all over every "flabby arm" thread I've seen for several years here on MFP. Here's a link to just one example:

https://community.myfitnesspal.com/en/discussion/comment/44618293#Comment_44618293

Try that, and see.