I’m a massive fan of the ideal here: if a source waives their anonymity, publish the full A/V source and transcript. Making these easy to consume is also key.
However, you’re not entirely clear on how you avoid the pressure to accept an anonymous source. If a story is huge, and the public need to know it (which, I imagine, will be true of a large number of your stories), there will be a lot of pressure to go with the anonymous source if that is the only thing backing the core of the story.
Internally — your journalists will develop a feeling about how trustworthy an anonymous source is, as you will know their identity and how accurate / truthful they have been in the past. Is there any way we can expose that trust chain to the audience in some way without compromising the identity of the source?