An equivalent concession would be the Confederacy ceding territory they firmly control or putting it up for plebescite. For example if the Confederacy ceded Indian Territory and put Texas, Virginia, North Carolina, and Mississippi up for plebiscite. That deal still favors the Confederacy, but it's at least equivalent.
The cession of crucial territory in Virginia in your treaty is by the Union, not the Confederacy. The Union have controlled Virginia north of the Rappahannock for years. Ceding any of that gives them a less defensible border and a less defensible capital.
Any Confederate demand for anything in Maryland is a bunch of hot air. They have never controlled it and never claimed it.
The Union would rather have a plebiscite in West Virginia than in Kentucky, Tennessee, Arkansas, or Louisiana. They know the Confederates can't cheat hard enough to win in West Virgina.
The Union would only ask the Confederacy to assume part of the Union debt as a bargaining chip. The Confederacy would be in even greater financial trouble than the Union, and would be expected to default.
Confederate claims for return or compensation of escaped slaves would be met and exceeded by Union claims for compensation over Union property seized by the Confederate government, debt owed Union citizens that the Confederate government forced Confederate citizens to pay to itself instead, and commerce raiding.
If the USCT are mutinying, there would be no demand for the return of USCT POWs. And a Peace Democrat certainly wouldn't trade that for a plebiscite anywhere, even if the ATL didn't require the USCT to be acting like idiots.
The Confederacy ceding claims to US Territory is significantly less of a bargaining chip than the US ceding claims to North Carolina, South Carolina, Florida, Georgia, Alabama, Mississippi, and Texas. It's certainly not equivalent to the Union putting any territory it controls up for plebiscite.