Requesting Assistance in Researching Vintage Shirting

Hello all,
I've began writing a series of articles, to document the various bits and bobs of vintage menswear in, as I should hope, for it is my intention, excruciating detail. This project's articles, in their current forms, will span over the course of the early Victorian era, to now, covering whatever observable trends I can muster, and prove to have existed. At the moment, I've just started on the section devoted to shirting.

But, all that is besides the point. I'm looking for resources regarding vintage shirting; Catalogs, articles written by other contemporary reenactors, and your own experiences with true vintage pieces would be greatly appreciated. While I do have a few specific questions, I beseech anyone reading this; If you have some usually useless knowledge regarding shirts and their trends (especially in the early 1900s), please, share! Any tidbit would be beyond appreciated, as would be photos of true vintage shirts.

So, my questions are thus:
1.) What was the point of a pop over shirt, with a half placket? I've spoken to a few vintage enthusiasts in the past, and their conclusion was that it was either: A), To save on the money, time, and effort required to affix so many additional buttons, or, B) Shirts had been made like that for so long, and no one cared to change it up. And, to add on to that, does anyone have concrete information regarding when this style went out of popularity?
2.) I'm planning to devote a short tangent regarding the many stories regarding the invention of the detaching collar. If you know any of these stories, and think one of them is particularly likely to be true, do share.
3.) On the topic of detaching collars, does anyone have insight into who/what prompted the sudden raise in collar height during the Edwardian era?
4.) Another on the topic of shirt fronts - Shirt bibs were very popular in the late Victorian and Edwardian periods, all the way into the 30s and 40s. But I can't find any information regarding why having a second layer of soft fabric on your shirt front was such a popular trend. Surely, it wasn't for the sake of durability - You don't wear out your shirt front.

Thank you all.

Regarding number 1: A full length placket serves little purpose when the trouser waist is extremely high, by which I mean sits at the rib cadge, a la mid-nineteenth century. The placket doesn't show and cannot be unbuttoned while wearing the trousers. Also, the unnecessary added bulk under the trousers can be annoying - particularity in periods where hefty small shirts and under drawers were ubiquitous.

Random factoid: During the 1920s to 1940s, shirts were more colorful than is generally assumed. Solid shirts that appear white in black and white films were, often, actually off-white, cream, pale blue, light gray, etc. Take a look at issues of Apparel Arts for examples of cloth types, colors and patterns during the 1930s; they are full of shirt ads, fashion plates, and sometimes fabric swatches. The patterns and colors are often quite bold by today's sensibilities.