SVG animation via WebVTT

I am coding a project, currently for personal use, that will modify MuseScore's SVG Export to produce:
- Modified SVG that includes "id" and other attributes that will be used by the animation program
- A WebVTT file (.vtt) that contains timing information linked to SVG "id"
see here for a more practical perspective on WebVTT
and here for a listing of browser support for WebVTT

Outside of MuseScore I am developing the WebVTT event handler, which will handle more than just the MuseScore sheet music SVG animation events - there will be more animated SVG than just the sheet music in the final display. The sheet music part of the event handler will be relatively generic, in that all the information for highlighting and un-highlighting the notes will be embedded in the SVG itself.

I am just now starting to write/debug code in Qt Creator, having just finished setting up for compile/link. From what I understand so far, here is my MuseScore coding plan:

1) mscore/file.cpp : PaintElements()
Exclude animated Elements from SVG output. Note Heads, Dots, Accidentals, and Rests are excluded via a new boolean function parameter that defaults to FALSE. This step is complete and debugged as of yesterday.

2) mscore/file.cpp: SaveSVG()
Change the call to PaintElements(), adding new arg set to TRUE, to exclude elements-to-be-animated.
Then add new set of loops to collect all the Note Heads, Dots, Accidentals, and Rests in playback order.
Then write the SVG and VTT files for these notes. This is a big step, which will have a bunch of sub-steps.
I am thinking to write the loops in this order:

for each Measure in the Score
    for each Segment
        for each Track           // track = voice ("channel" in staff.cpp) across staves, right?
            for each ChordRest

Inside each ChordRest are the elements I need, including the ticks which I will attempt to convert into elapsed time via the score's TempoMap::tick2time() function. WebVTT is text that deals with elapsed time, in a fixed format, to the millisecond: HH:MM:SS.000. Here is a first sketch to get me to the ChordRest level in C++:

      foreach (Measure* m, score->measures()) {
          foreach (Segment* s, m->segments()) {
              for (int i = 0; i < score->ntracks(); i++) {
                  s->cr(i); // each and every ChordRest in the Segment/Measure/Score
              }
          }
      }

I have looked at renderMidi() (rendermidi.cpp) and fixTicks() (score.cpp) as well as various other functions that loop around ChordRests, in and out of playback order, and I am emulating those to collect my Elements.
I am not dealing with RepeatSegments yet, though it seems straightforward enough to add them using rendermidi.cpp as the example, so I plan to tackle that after I get the basics working.
I will add Swing next, similarly using rendermidi.cpp as the example.
I don't yet want to consider grace notes, arpeggios or other Articulations that rendermidi executes because they require additional graphic types beyond note heads, dots, accidentals and rests.

I think that's it for now. Any suggestions are welcome. I can already see that I've left out Lyrics :-)