With Mama out of the way, one or both of the fawns may stick around.

Mama also appears to have taught the fawns your feeder, it's benefit, and your appearance as a non-threat. Learned feeding behavior like that is life-long lasting. The only possible mishap would be the surrogate doe, if she is different in behavior, the fawns may revert to her habits.

Sorry to hear about that. But a great experience nonetheless.