FDR - CVR
The FDR probably will show a normal flight, then maybe nothing. Maybe. The avionics area would have been badly fragged, but the front section did not separate immediately. Nor did the tail section where the recorders were, so it could have continued to record until the wiring to the tail ripped. This would tell us when the port engine was lost and how long the starboard engine had fuel, which could reflect on where/when the main tanks ruptured. It won't help with cause, which is already known. It would help map the breakup.
The CVR will be able to settle three points
1: discussions with ATC about route or altitude changes
2: do these match with eventually compared ATC recordings which were "confiscated" at the time
3: any mention of fighter escort or activity nearby
The missile impact may be on it or not. Probably yes. But this is not important, as the skin is full of evidence.