Hello Anne,
The simple answer to your first question is yes. Within the table of contents, there are no blank lines between consecutive centered headings and the transcriber created volume divisions regardless whether they are 1, 10 or Following Volumes. There are numerous examples in the samples portion of section 2 of the braille formatting guidelines.
As for question 2, braille formats 2.12.1 states: “The first item listed in the table of contents is generally considered the first page of the main body of the book.” The key word is “generally” as there are always exceptions that requires a transcriber to use their judgement. A good general rule is to look to braille formats 2.7 Front Matter Basics through braille formats 2.11.Other Front Matter. This will help you determine what material would be considered a preliminary page and what is the point at which body matter starts. The inclusion of roman numerals can also be helpful in distinguishing between preliminary and body material.
Also remember that while the training program is an awesome resource, when it comes your manuscript do not forget to reference the braille formatting guidelines as well.
Mike