So basically MVP is about deliverable with particular value to a customer (A minimum viable product is a version of a product with just enough features to satisfy early customers and provide feedback for future product development).
As for the scope of work called "Phase 1" there are no mandatory obligations to be a version of a product. It could be just a preparation step (eg infrastructure setup) or any other sequence of work that drills down to some joint result you specified.
Edited according to author's change. Probably you need to add a glossary for the project you are involved and then make sure all required persons have shared understanding of it.