Are "bonefish flies" tied with calftail and material like this because the wing is typically shorter than what you'd get with bucktail?....just like what I'm going for? I've never tied bonefish flies and am not familiar with them.
There are many types of "bonefish" flies. My comments were more about those that are tied in the style that resembles Clouser Minnows. Patterns such as Crazy Charlies or Gotchas. Gotchas are typically tied with synthetic materials in the wing, but such hairs as fox can also be used. Clouser Minnows, being extremely versatile, are also popular as Bonefish flies. The majority of "bonefish" style flies are tied in sizes ranging from size 8, up to about size 1 or 1/0, with 6, 4 & 2 likely the most used sizes, so yes, calftail is used because it's length fits these sizes well.
I like the Crazy Charlie style flies for Smallmouth bass in streams. Since the style is intended to imitate various small shrimp, it works well as crayfish too.
I'll adjust the colors to better fit those of the crayfish in my area. Squirrel tail, as Rip Tide has indicated is a material I like for such patterns, as it's natural coloration & barring fits crayfish patterns & the fine texture of the hair works well on small sizes.
Prior to the 70's, calftail & bucktail were both used extensively in many saltwater patterns, including Bonefish flies, primarily because there was not as yet the proliferation of materials in wide use that we have today. Both materials were also readily available & relatively inexpensive. Both, are still popular & still used, but since other materials are now more easily obtained, tiers do not limit themselves to what used to be standards. Calftail has also been a very popular material for small jigs such as Shad Darts, used for Shad & various panfish species.
If you take a look at many of the older Steelhead patterns, such as Skykomish Sunrise, or Polar Shrimp style flies, they were commonly tied with either Calftail or bucktail depending on the sizes. Today, as with saltwater patterns, there are many more materials available.
A Google search for "Bonefish flies", or "Crazy Charlies" will yield many images of small size flies that can be adapted for the type of fishing you're looking to do. Just be sure to use materials that fit the sizes you tie to get the most from the patterns!
BTW, just to throw a wrench into this discussion, ostrich herl fibers also work well for small flies!