The Federal armies routinely seized several classes of property belonging to Confederate civilians. They seized horses, hogs, mules, slaves, houses, real estate. Ask the people that lived in the Shenandoah valley what property General Sheridan seized. As the people of central Georgia, South Carolina and North Carolina what property General Sherman seized.
Whether legal or not is again your opinion. What cases before the courts decided that seizing the property of those in insurrection was Unconstitutional
To be equivalent, you would have to seize all of the property of everyone without trial, not just a select few in places that were beneficial to the military at the time.
Let us say that Lincoln made a proclamation to seize all the horses, hogs, mules, houses, and real estate throughout the entire south.
Would this have been legal or constitutional?