fronting

As to fronting, I have some questions.

e.g. ? To this list may be added ten further items of importance.

? She might agree under pressure : willingly she never would.

? Of all the early examples of science fiction, the fantanstic
stories of Jules Venre are the most remarkable.

The underlined parts are all fronted to the initial position.
And here are my questions.

a. In terms of the value of information, where is the part of the
sentence that the focus falls on, the fronted element or the end of
the sentence?
(What I mean by the 'focus' is concerned with two facets, the
stress and the significance of the information each.)

b. By Quirk, the fronted part is the marked theme and itself can be
the given information when the fronted element includes
such words ; this, that, these etc.

e.g. Most of these problems a computer could take in its stride.

Then, the reason to use the fronting structure is that the speaker
intends the hearer to be relaxed at first by saying the familiar
information and then the speaker says something new so as to
surprise or attract the hearer, which is just my guess.
Is my thinking right? What is it that you have in your mind when
using the fronting structure?

c. As you see ?, there is a comma in the end of the fronted
element. But the others have no comma.
So under what condition should the comma be used?

d. Should the fronted element be the information having been
known to both of the spekear and hearer?
What if the information new to the hearer is used in the fronted
position?