Plasma is a bit hotter than your gas fireplace flame. Common lighter flame is at about 600 deg C and while it's possible to create plasma which is nearly ambient temperature in controlled environments it's generally tens of thousands of degrees (plasma arc welding for example) up to tens or hunderds of million degrees celsius (inside fusion generator).

That's mostly why fusion energy is so difficult problem to solve in the first place as there's no materials which could withstand the heat. So, no, it wouldn't be useful as a fireplace. It would of course radiate heat, but it would also light your (and your neighbours) house on fire, so not that useful.

Nuclear fusion will happen inside a power plant far away and homes will get the electricity like from any other power plants. So no.

The fusion is activating the walls of the reactor, they get somewhat radioactive.

Even if your home is powered by nuclear energy, you still don’t have uranium fuel rods in your fireplace.

Plasma for fusion is at insane temperature and pressure to make fusion possible, to overcome the repulsive force that keeps protons apart by sheer velocity of the colliding nuclei. So you wouldn't have that kind of plasma in a fireplace generally. But you can get room temperature plasma today without fusion, look up plasma balls... That could make a cool (but not fire-like) fireplace, if it could be engineered into another form factor