Congratulations!
here’s what I’d do.
To make life easier for you and those downstream while also being prepared for the unknown…
Go to your original music session and stem out the whole song into manageable food groups. Any musical tweeks you want to do should be done first.
These stems, at unity, should more or less equal your mix. if it doesn’t, go back to step one or make global changes with clip volume etc. Edit these stems to picture to match the picture editors work, then clean up the edits to make them smooth and musical.
Music adds and samples will go on a new track and get they’re own stem.
Now you can prepare new stems for each track that are locked to each picture edit. These can be sent on to the mix. Rule of thumb… always assume the next person down the line is way to busy to figure anything out. include 2sec sync pops and keep it simple.
If you are doing the mix also… I’d still suggest you do it this way. Especially when picture is involved, and especially especially when multi versions are involved… having tangible pieces such as finite labelled audio files helps.