QM35825 modules (with / without host MCU), Apple Nearby Interaction and DL-TDoA support?

There is not a module offering for the QM35825.

There is not an example, but the NI would be implemented on the host processor and then control the QM35825 over UCI.

Yes, the QM35825 is the recommendation for developing a FiRa DT-Anchor or DT-Tag. An example of it can be found in the SDK: Samples/Python/UWB-Qorvo-Tools/scripts/fira/run_fira_dt · main · QORVO_SDK / Public / DevKits / qm35-sdk · GitLab. It has been verified with iPhones though Qorvo is not providing an app for this.

We don’t necessarily have a limit. The limit would mostly be a limitation of the available radio time.

Yes.

Yes, this is correct.