"Provided for" can have a range of meanings from tolerance to endorsement. The constitutions were not equivalent in their treatment of slavery.
So which constitution has the language "no bill of attainder or ex post facto law shall be passed" and which one says "no bill of attainder, ex post facto law, or law denying or impairing the right of property in negro slaves shall be passed?"
Wasn't West Virginia admitted to the Union only because it had an abolition plan? Is that explaining it away? This doesn't seem inconsistent with eliminating slavery.
“Wasn’t West Virginia admitted to the Union only because it had an abolition plan?”
No.
West Virginia was made into a state because Lincoln considered it was in his best military, economic, and political interests.
But if you want to make the case that Lincoln created and brought a slave state into the union so that he could “free the slaves”, then go ahead.
You could probably make a stronger case that Lincoln’s decision to create a new slave state was an insincere political shenanigan. He was very good at that. Six hundred thousand widows will agree.