Team up with the other senior developers to hire a senior, yes senior, labor lawyer and have him get to work on laying the groundwork for an age discrimination

Team up with the other senior developers to hire a senior, yes senior, labor lawyer and have him get to work on laying the groundwork for an age discrimination class action lawsuit. His/her advice will be for everybody to begin a diary of interactions with management and retrieve what each individual can of their history with the employer. This is the time for everybody to copy and/or print your emails and other interactions with management to a place where you can access them after being frog marched out of the office. Work from home situations make it easier to preserve the data your lawyer wants preserved. A good labor lawyer representing several senior developers will know if / when it might be advantageous to fire a shot across the bow before terminations - AFTER s/he has complete documentation. Oh yes, be very sparing in documentation of the processes you babysit. My last multinational manager had me spend a half day to describe my weekly database update procedure to a well connected lady who had never seen a SQL statement before. That system slowly sank into the sunset as several more years and megabucks were expended on head office's chosen replacement.