We are to follow print for capitalization, yes. But the use of small caps is not capitalization. Capitals may be used within small caps, but small caps themselves are not capitals.
Small caps need to be shown where distinction or emphasis is required for the understanding of the text. “Foreword”, etc., are already set apart with a blank line and indention. Further distinction is unnecessary. Nor do these entries need to be emphasized in any way. Therefore, the identification of small caps is not shown. Because of all this, Braille Formats 2016 2.10.8 says to use title case for small caps in a table of contents.
The example of PT109 in UEB 9.6.1 is showing an abbreviation in small caps. As explained in that text, abbreviations in small caps are generally transcribed with capital indicators. The following example in UEB 9.6.2 is showing an example where distinction is necessary. The heading must be distinguished from the surrounding text. Once it’s decided that distinction or emphasis must be shown, THEN the transcriber should follow print. Italics, boldface, underlining, or script indicators are not options here because print did not use those typeforms. A transcriber-defined typeform indicator must be utilized.
The forum post from 2010 was pre-UEB and should not be referenced. Also, be careful about treating the lesson manual as a rule book. While it has many useful examples and explanations, it is not a definitive source for transcription. Do follow it for your manuscript submission, however.
“(cont.)” in the table of contents does not need to be in transcriber’s note indicators because the writers of Braille Formats 2016 decided that the existing parentheses were sufficient. Adding TN indicators would mean five cells of indicators on either side of the abbreviation. See BF2016 2.10.10.