:I'm not sure what all the issues have been with your edits and the rest of the community. As best as I can determine, the issues are 1) use of code share in lead & 2) changing tense "is" to "was" (based on this edit). In regards to Wikipedia:AVINAME, the guideline is the following (abridged for clarity): 
"Where an aviation incident article...begins with the opening sentence: Airline Flight XYZ...., it should go on to immediately describe the notability of the incident in as few as words as possible. For this reason, it is not necessary in the opening line to clarify that the flight number may still be in use, or where it is normally scheduled to fly - this is because the normal flight or flight number is not the subject of the article...For example: Madeup Airway Flight 123 was a passenger flight from Somewhere to Somewhere Else, that on such and such a day, failed/crashed/blew up/was hijacked. [correct]" 
I think the important part of the guideline is what I italicized. I think the code share is important, especially given the media coverage focusing on the men traveling on stolen passports. Whether or not that belongs in the lead doesn't matter to me...it could be a separate sentence or mentioned in the "incident" section. Take a look at the example given in the guideline—Air Florida Flight 90—and the recent high-profile, highly-edited article Air France flight 447. Both use two sentences, first being to state the origin/destination and the second stating the aircraft & what happened. I don't think there needs to be a reference to the men using stolen passports, as officials do not believe they have links to terrorism. It's also difficult to write about the significance of the flight without referencing it as "crashed", per Wikipedia policies. Taking into account what I said, here is a proposal for the lead:

If an official would just refer to the plane as "presumed crashed", then the following could be added as a second paragraph in the lead:

Thoughts? A good compromise?