Well, I haven't had a Bianchi holster since my 4L was sold along with its H&K, but I'll make some comments.
The 19L is a conventional belt holster, suede lined to protect the gun blue. You have to keep that suede lining clean or it will hold grit and do a worse number on the gun than plain leather or Kydex. No, it does not come with a belt although they will be glad to sell you one. Wear the widest and stiffest belt your belt loops will accomodate. A GOOD 1 1/2" belt is ok, 1 3/4" is better if your pants (skirts?) and the holster will take it.
The 58L and 59 are two varieties of paddle holster that do not require a belt threaded through loops. I have several of other brands and always wear them with a belt. I think it would take a very stiff waistband to keep them from flopping around without a belt.
The 99 Border Patrol is for a Sam Browne (police uniform) belt and I don't think it suitable for other use.
All the holsters you list are thumb-break type, with a strap and snap that you have to learn the motion to release. I prefer an open top holster like the 4L, the Safariland 5181 or their 560 that I just draw the gun from with a straight lift. There is enough friction and molding to retain the gun through all but the most strenuous gymnastics. I haven't dropped a gun out of a holster yet.
All the holsters you and I list except for the 99 uniform rig are high-ride holsters. If you are not rather long-waisted for a lady, you might find them too high, leading to an awkward draw and less comfort. The Safariland 560 paddle type is a bit lower, but not a lot.
Several Kydex benders like Blade Tech and Talon Tactical make holsters with more drop specifically for ladies. You will have to wear a bit longer jacket to cover, when and if, but the carry and draw will be better. There are those who say Kydex is harder on the gun's finish than leather. I don't know, but I don't worry much about it.
The only leather holster I know of for women is from Kramer, who says:
Woman's Belt Scabbard, FBI Forward Tilt
Finally! A holster designed specifically for women. The complaint we hear most frequently from women is that their holster "rides way too high, and the grip of the gun is up around my armpit." A holster designed around the male body will ride uncomfortably high on a woman.
A woman's curving hips tend to push the muzzle of the gun outward, causing the grip of the gun to jam into her ribs. The Women's Belt Scabbard carries the gun at a lower, more comfortable and accessible position for a woman.
The belt slot is lined with molded plastic, formed at such an angle as to tilt the grip out slightly, preventing it from jamming into the rib cage. The weapon is carried on the strong side at an FBI tilt. This holster must be worn with a sturdy belt to support the gun. This holster has received overwhelmingly positive reviews by gun writers, and female law enforcement officers.
http://www.gokart.net/cgi-bin/store.cgi/kramer?page=/index1.html&cart_id=%%cart_id%%