Since a lot of this seems to address the preferences of guys, I will address them from my point of view as a guy.
I've preferred small breasts all of my life. Almost every gf I've had has been an A or B cup. That's what appeals to me. Didn't see a D cup up close and personal until I was about 40 and it was mostly, meh. No big deal.
Well, that is one reason that I seem to prefer women with small breasts. Although some women with large breasts can be thin, (especially if the breasts are bolt ons), that doesn't seem to be the rule, at least from what I've observed. So, I can't see that being an issue.
That seems to be the case when a women is aroused and if you are comparing that to women in photos, my guess is that models in photos are anything but aroused when posing for a photographer and crew.
You stopped short on your research. That 4-5 inches of the average vaginal canal refers to the length when a woman is not aroused. Arousal can cause it to double in length as needed.
Not quite sure what you are referring to here when you say loose on the outside. As for the labia (which I assume is what you meant by size, earlier), I think that's a personal preference. I actulaay find longer labia minora that protude out to be a turn on, and to be quite honest, in all of my years, I have never heard a guy say much of anything either way about labia size. I'm really not sure how this notion of labiaplasty ever got started, but trust me, guys in general are not going to pay that much attention. As for being loose throughout, yes, that's possible, but my personal experience has been that tight has a lot to do with physically fit, so exercise would be helpful if you really thought there was a problem. Most likely, you are not unlike the rest of us who would like to be greek gods and goddesses, but are stuck with being normal people with normal bodies.