Thanks everyone! Always inspired and uplifted by the ski community's willingness to help others :)
In regards to set up, as @6balls said, I received the ski from him. Having only started seriously skiing last year and now only about 4.5 total months in the course under my belt, I unfortunately really know nothing about ski set up, especially fin adjustments, and do not own calipers. I really do want to learn though, and this has spurred me to reach out to my current club and I believe I'll be able to do a "tutoring" session with a fellow skier. At that time I can measure my current fin and let you guys know. I am running it without the wing on. Time to search BoS for caliper recommendations lol.
At my (different) club last year, someone who said they knew what they were doing, after watching me ski, made some fin adjustments and also recommended moving my boots back one notch. I do not know specifically what fin adjustments he made, but I did move the boots back. Especially back then, my skiing was inconsistent and unfamiliar enough simply from a technique and awareness point of view that I couldn't say for sure whether the adjustments were any better or worse. Note that the ski is 67" and I only weigh 155-160 (first thing in the morning), so my understanding is that 67" is a touch long and a 66" would be more ideal.
Since this maybe has also turned into a "ski set up recommendations" thread, here is a much more successful pass from a week before, probably my best of the year (despite running over 1 ball), in order compare the good vs. the bad:
Back to the fall, a lot of the technique recommendations from @MISkier, @6balls, and @braindamage make a lot of sense to me. I can definitely see how I get disconnected starting at the wakes, relax my body stack, stay flat, and roll onto the back of the ski.
The fin definitely didn't fall off. In regards to hitting something, there are a lot of small turtles at the lake. But the fact that I fell in a very similar way on a different lake last year makes me think that's less likely. Here's that video as well: