It is possible for EAD to get approved without L-1 getting approved. Seen that happen several times. There is no harm in filing. You can stay in the country as long as your L-2 extension is timely filed and pending. You cannot however work till EAD approval. Good luck.
You appear to be concerned about your lawful stay in the United States and wish to remain in the country legally. If that is in fact correct, delegate any of your issues to the counsel of record, as legally appropriate in this situation.
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Undoubtedly you already have an immigration attorney, and you should ask the attorney these questions.
The above is intended only as general information, and does not constitute legal advice. You must speak with an attorney to discuss your individual case.