[q1w2]

This becomes a semantic debate if we do not define the boundaries between models. If models are "integrated" to an extreme, then they are really just the same model. ...the tradeoff of having one model vs two models is often driven by resources used to hold and serve content from a model, but there are also mathematical constraints as, for example, the size of the model grows in proportion to the quadratic of input data, which means that separate models which can communicate with one another are more efficient.

...but the trick is defining that inter-model communication and establishing a "controller" model with appropriate training data.