The issue there is that at one point Calvin left Hobbes at home by accident when going on vacation. When they went back for him the house was not being robbed... as in they fled the house so fast that they left their tools behind. The issue then is that stuffed Hobbes was also in a different room than when they left on top of something too tall for Calvin to put him on. This was noted by Calvin's mom. Hobbes left it open whether or not he claims to have eaten them.
This means at the very least Hobbes can move around his stuffed animal body on his own. This would explain the Calvin tackled when opening the front door thing. This mean Hobbes can physically interact with the world.
The issue of Hobbes and Suzy having conversations is also up in the air as if she can see him, though this could be Suzy and/or Hobbes trolling Calvin.
This means at the very least Hobbes can move around his stuffed animal body on his own. This would explain the Calvin tackled when opening the front door thing. This mean Hobbes can physically interact with the world.
The issue of Hobbes and Suzy having conversations is also up in the air as if she can see him, though this could be Suzy and/or Hobbes trolling Calvin.