What I see is basically three major factors contributing to what we think of as female beauty.
Sexual attractiveness characteristics are the fundamental underlying trends which tend to be universal and convey direct advantages in terms of fetility or disease-resistance. The 70% hip/waist ratio (indicates fertility), even features, clear skin & healthy hair are examples. These can be seen not only across cultures but are also constant over very long time periods.
Cultural norms tend to be different in different cultures and change as the culture changes. These attributes help determine each person’s place in the social heirarchy which in turn allows each person to maximize their wealth/power. Wealth/power is important in gene survival because the more wealth/power you have when necessary resources such as food are scarce, the more likely you will be to get an adequate share to keep yourself and your children alive. Also, adhering to cultural norms indicates you are willing to be a part of the culture and not rebel against it. This may be unnecessary in modern culture; however, in a situation where everyone in the group must cooperate for the group to survive, it can be critical. Note that in the historical context, cultural norms can change very quickly. A particular culture’s norms may be counter-productive in evolutionary terms but not have been around long enough to have been bred out.
Fashion - what most people don’t seem to realize is that fashion has precious little to do with beauty, except in that fashion uses beauty to further its goals. In the past, fashion was a product of conspicuous consumption: whenever the fashions changed you had to buy all new clothes, something only the rich could do. That has fortunately changed; however, the fashion designers still have to sell clothes. They do this with fashion magazines, runway showings and constant changes to what the “look” is supposed to be. (Did you know that there is an organization that determines the “in” colors 4-5 years in advance & companies pay $1000 dollars to get this information?) Runway showings are pure marketing - the wilder the fashions, the more likely a designer is to get his or her work and therefore name in newspapers across the country. Fashion models are selected solely on their ability to make the clothes look good and to convey the proper look which goes along with the style. That the models are beautiful is almost incidental - they are only beautiful because that makes the clothes look better. This is also the reason why they tend to be slender if not downright anorectic - women of this shape tend to wear a larger number of styles well. In addition, it’s easier to construct garments for women with no hips or busom.
Now, to get back to the OP: most of the things on your list probably started as an attempt to achieve a desirable sexual characteristic such as small feet or long necks. Over time they
a) became more & more extreme until they were destructive
b) became symbols of wealth, then spread throughout the population
c) eventually became so pervasive that to not bind feet, elongate your neck or whatever would have the force of taboo.
In addition, our ability to modify our bodies can far outstrip the speed at which evolution works.
How did boyish hips and an improbably low percentage of body fat become attractive to men (myself included)?
Are you sure? See if you can get the waist and hip measurements of your favorite model or actress then calculate the ratio - unless you’re a fan of Kate Moss, I’ll bet the ratio is closer to 70% than 100%
Heroin chic was a look devised by fashion designers, not a beauty standard. As I recall, it didn’t last very long either. Twiggy actually had a 70% h/w ratio. And “healthy” is not as much a factor in beauty as disease resistance.
When food was scarce, having extra weight meant that you got more food than other people (more money/power) and were also more likely to survive a famine. Now, overweight says you’re not taking care of your health, or you are too poor to eat healthily (of course, these aren’t necessarily true) Also modern fashions and the camera are very unforgiving to larger women.
Actually, this could be advantageous in evolutionary terms. If a woman survives the infections associated with these practices, she probably has more disease resistant genes than someone who dies from the process. And the various painful rites of passage applied to boys may help them face and conquer fear of pain - necessary in an environment where going to get supper carries the possibility of maiming or death, and hesitation means the difference between starving and eating.