Protestantism in general has focused for centuries on what a person does during their life rather than what they believe (in contrast to Catholicism, which tends to focus more on the latter). The Quakers merely took that one step further (they are, after all, a branch of the Protestant subtree of Christianity) by acknowledging that a person could be good without believing (all or even any of) the things that Quakers believe.

It is not picking through or over the bones of Quakerism to grapple with and/or be inspired by this idea.

As for Stoicism, I am not sure that it is required to do anything other than, maybe, bring greater peace and understanding into the lives of those considering its values.