Is incognito breast surgery possible with smaller, “soft” tissued breasts? (Photos)

You appear to be a good candidate for breast augmentation.  The softer, more natural feel tends to come from the silicone implants.  Smaller implants tend to have a more natural look than larger implants.  Shaped implants will help mimic the natural slope of your breast, but will give less of the rounded, upper pole fullness.  I recommend beginning by scheduling a consultation with a board certified plastic surgeon near you to learn what is best for you.

Good questions. Much of the final look and feel achieved after breast augmentation surgery depends on several factors:
1. The initial shape, size (volume of breast tissue), symmetry of the patient's breasts. In general, the better the preoperative breast appearance the more likely the breast augmentation “look” will be optimal. In your case, your breasts are constricted, demonstrating features such as white aerial, short distance from area looks and for manifold, and relatively wide to space between the breasts.  The outcome of surgery will be limited, based on your starting anatomic features, to some degree. Your goal of old photographs are not realistically achievable.
2. The experience/skill level of the surgeon is important in determining the final outcome. For example, the accurate and gentle dissection of the breast implant pockets are critical in producing long-term well-placed breast implants. I personally think that these 2 factors are more important than any others, including type (saline or silicone) or model (low/moderate/high profile) of implant.
3. The type of implant used may determine the final outcome, especially if the patient does not have significant covering breast or adipose tissue. For example, some surgeons feel that silicone implants have a more natural look and feel than saline implants because silicone gel has a texture that is similar to breast tissue. In other words, if a patient has very low body fat and/or very little breast tissue, the silicone gel implants may provide a more "natural" result. I find that I use round smooth silicone gel breast implants for the vast majority of patients who seek breast augmentation surgery.
4. The size and model of breast implant used may make a significant difference in the final outcome. Therefore, it is very important to communicate your size goals with your surgeon. In my practice, the use of photographs of “goal” pictures (and breasts that are too big or too small) is very helpful. I have found that the use of words such as “natural” or “C or D cup” etc
Also, as you know, cup size varies depending on who makes the bra; therefore, discussing desired cup size may also be inaccurate.
  To summarize: select your plastic surgeon carefully. Communicate your goals carefully as well.  Chances are (assuming realistic expectations) that you will be pleased with the outcome of breast augmentation surgery. 
I hope this helps. Best wishes.