Right.
Corwin simply tried to match one protection for slavery that was already in the new Confederate constitution.
"Article I Section 9(4) No bill of attainder, ex post facto law, or law denying or impairing the right of property in negro slaves shall be passed.[13]"The 1861 Confederate constitution included several other protections for slavery which neither Corwin nor the existing 1787 Constitution could ever match.
Wrong. The Corwin Amendment was introduced on March 2 and was ratified by the Senate on March 4. The Confederate Constitution was not introduced until March 11. The Corwin Amendment preceded the Confederate Constitution.
In addition to getting the timeline wrong, you are also wrong on the facts. The Corwin Amendment would have provided all the protections for slavery that existed in the Confederate Constitution with its ban on the Confederate Government imposing abolition of slavery on any state.
Of course, the Corwin Amendment was just spelling out explicitly what already existed de facto. The US Federal government had no power to abolish slavery in any state even if there had been widespread support for abolition which there wasn't.