Putting "List of Figures, Tables, Conference Talks, etc." in thesis (Chemistry)
Ok, there are two questions here, so let's go one by one:

For the list of figures I think you can put them without problem. They take maybe one or two pages, and that shouldn't make a significant difference that could be considered "page filling". If two pages are 10% of your whole thesis, then you still have work to do.
Especially if you refer to figures during your thesis, it is great to have a list, including page number, instead of having to search every time.

About conference talks: In my understanding (coming from a mathematical background), a PhD thesis is a long, more detailed (and hopefully really good) research paper, that might be read by other scientists. Thus, putting in conference talks seems like begging for a better grade, like "see how great I am, I even went to these conferences", something that has no place in a scientific work.
While going to conferences is surely important, I think it should not be put into the thesis but mentioned at a different place. As your advisor is surely aware of the conferences you visited, ask him how to best communicate this fact to the committee.