This project is a fea analysis on an accumulator container that we were designing .I am not able to generate a tet dominant mesh for this ,mesh event log says that a problem occurred in the surface mesh generation, but a standard mesh with fineness level 5 is generated successfully.
Your first and third mesh were created with the Standard mesh algorithm and they meshed successfully. On you second mesh you tried the Tet-dominate mesh and it failed. In general the Standard mesh algorithm is much more robust and will usually be more successful.
In my experience I have not had a case where I needed a Tet-dominate mesh (mixing tets and prisms).