Anime Insert Song Synchronization

I have an MKV file of an anime episode that originally featured an insert song during a key scene, but the current version is missing it. I need that track sourced again (I no longer have the audio file myself) and placed back into the scene so that every cue, beat, and transition lines up perfectly with the on-screen action exactly as in the older release.

Here is what I expect:

• Locate a clean, high-quality copy of the exact song—whether from an official OST, Blu-ray rip, or another reliable source.
• Cut and align the track so it matches the original timing of the scene frame-accurately; dialogue, SFX, and overall mix must stay untouched.
• Deliver a finished MKV with the song seamlessly integrated (same video quality and audio channels as the source) plus a short change log noting the in-out timecodes you used.

Acceptance criteria: when I play the final file, the insert song begins, peaks, and ends in perfect sync with the visual moments it was meant for, with no noticeable dips, overlaps, or audio artifacts anywhere else in the episode.