Article VII, Section 2 states in part:
The Convention shall be constituted under regulations determined by the Senate.
Clause 4 of the bill is such a regulation. The Convention may not simply ignore it.
The Senate may only regulate how the "Convention shall be constituted," i.e., the composition of the Convention. The composition of the Convention is different from its agenda.
In any event, Clause 4 states that the Convention shall discuss the system of government. It does not state that the Convention shall discuss
only the system of government.