My comment was directed to your statement that before the South had been admitted to the confederacy, and long before secession had even been approved, Virginia had already joined the rebellion by seizing the arsenal at Harper's Ferry and the navy base in Tidewater. Whether or not they had formally joined the non-existent, in Lincoln's eyes, CSA was irrelevant.
The "temporary convention and agreement" permitting the admission of Virginia into the CSA for safety and defense purposes was on condition that it be approved by the appropriate authorities in both governments. The voters were the appropriate authorities in Virginia.
A look at all the legislation passed on May 7 doesn't show the words 'temporary convention and agreement' in any of them. Link
From your link:
Resolved by the Congress of the Confederate States of America (two-thirds of the Congress concurring therein), That the Congress advises and consents to the ratification of the convention and agreement entered into on the twenty-fourth day of April, eighteen hundred and sixty-one, at Richmond, Virginia, between the Commonwealth of Virginia, by her commissioners, and the Confederate States of America, by their commissioner, the Honorable Alexander H. Stephens.
I take it that you haven't looked at the "convention and agreement" that the Confederate Congress advised and consented to the ratification of in the paragraph above. That document itself clearly states that it is temporary. Alexander Stephens, when imploring the Virginia Convention to agree to it in April, called it a "temporary alliance."