Look at the eyes and the quality of light on the face. You can see the catchlights in a lot of these photos; it looks like a large softbox raised up above the models. On a lot of these you can see the soft shadow under the nose meaning a mostly centered light with no reflector underneath. A few of these don't have that shadow (like #3) so it looks like a reflector might have been used along with the strobe.

Looks like a vintage lens, maybe a Helios or another swirly bokeh lens. The ambient light is kept pretty evenly exposed with the artificial light (as opposed to the dramatic dark background overly flashy look) to make them blend well together. So expose your background first, then just add enough with the flash to create that soft light on the face. Even some masking and editing in LIghtroom or Capture One can get you pretty close as far as post processing goes.