The acts of secession were legislation passed by the Texas legislature, and which violated the Constitution.
The powers not delegated to the United States by the Constitution, nor prohibited by it to the States, are reserved to the States respectively, or to the people.
Approval of actions concerning the status of states was a power delegated to the United States Congress by Article IV of the Constitution.
Full Faith and Credit shall be given in each State to the public Acts, Records, and judicial Proceedings of every other State.
When those public Acts do not violate the Constitution, yes.
Where do you find this stuff? From some 'moderated' forum? The state of Texas elected delegates to the convention 8 Jan 1861, with the convention meeting in Austin on 28 Jan 1861.
John R. Baylor was a delegate - he was not a member of the legislature. Neither was delegate Albert C. Horton. And judge John Gregg, judge John Ireland, M. T. Johnson, William B. Ochiltree, Williamson S. Oldham, L. A. Abercrombie, Joseph H. Dunham, J. L. McCall etc. It was not the legislature that met.
After opening with prayer, the convention elected Texas Supreme Court Justice Oran M. Roberts as president, who declared, '[a]ll political power is inherent in the people. That power, I assert, you now represent.' On 1 Feb 1861 the convention voted 166-8 to secede. The convention also allowed the people to vote on secession, which passed 44,317 to 13,020 on 23 Feb 1861.
John McQueen, special commissioner to the convention from South Carolina, addressed it 2 Feb 1861:
Mr. President and Gentlemen of the Convention, I have been honored with a commission by the Convention of the State of South Carolina to repair to your State and lay before your Convention an ordinance of the State of South Carolina ...
You can read about the convention in Journal of the Secession Convention of Texas edited by E. W. Winkler, and published in 1912.
Approval of actions concerning the status of states was a power delegated to the United States Congress by Article IV of the Constitution.
No. Only the admission of NEW states was regulated.
When those public Acts do not violate the Constitution, yes.
No. Please re-read the Supremacy clause.