You do realise as a photographer I'm now going to ask you for the ability to control the depth of field by selecting an aperture setting from a drop down box (f/1.0 - to f/22) and also the ability to choose the point of focus

As an amateur photographer myself, I would be tempted to add these settings myself too. But as Sweet Home 3D developer, I prefer to keep it simple and propose more depth of field choices to advanced users.
The idea I have in mind now, is to propose maybe 6 different "depth of fields" in the Lens combo box:
- Short depth of field / Focus 1m,
- Short depth of field / Focus 2.5m,
- Short depth of field / Focus Infinity,
- Great depth of field / Focus 1m,
- Great depth of field / Focus 2.5m,
- Great depth of field / Focus Infinity.
What do you think of this idea?

Are the new larger size lights available to download or does the new plug-in interpret the 3 lights as a larger by default?

The new plug-in interprets all light sources as twice larger.

If you want to create soft shadows maybe you could use reflected lights close to a shiny surface or an umbrella as a real photographer would do. [;)]
In case you need it I created the umbrella 3d model you can import.