Q:
How can we iterate through all glyphs on a page (including extrapolated spaces) and retrieve bounding boxes (or quads) for each glyph as well as the text associated with that glyph respectively?”
A:
You would use pdftron.PDF.TextExtractor as shown in TextExtract sample:
https://www.pdftron.com/pdfnet/samplecode.html#TextExtract
https://www.pdftron.com/pdfnet/samplecode/TextExtractTest.java.html
You can get a bbox for every line, word, or a character:
https://www.pdftron.com/pdfnet/mobile/docs/Android/pdftron/PDF/TextExtractor.html
https://www.pdftron.com/pdfnet/mobile/docs/Android/pdftron/PDF/TextExtractor.Line.html#getBBox()
https://www.pdftron.com/pdfnet/mobile/docs/Android/pdftron/PDF/TextExtractor.Word.html#getQuad()
In case you are referring to WebViewer (https://www.pdftron.com/webviewer), we offer the same functionality there, but the API is a bit different.