"are anticipating delays in the process"

Taking the RMD is about a 15 minute process. The Executor (not the beneficiaries) would do this, as it is under the dead person's SSN. There are two weeks to do this one task.

"There is no exception on Form 5329"

You include an explanation for waiving the penalty, but they should not need to bother. The RMD is a snap. It might be allocations or distributions that take a while, when there are multiple beneficiaries and if that includes a spouse, etc. That complexity can delay things. Even then, two weeks?