The question can be explained by Force Equilibrium equations as stated by @Alex Doe . Therefore we are actually trying to conclude two variables which are Force and Work. You are trying to question if there is a force exerted internally in system, is there any chance to cause work done by the body. To make it more clear I again made a similar Force Equilibrium diagrams which I am giving here.
In the case 1, The forces net force that needs to be exerted is
"Force =Mass * g"
In case 1; According to newton's third law, Every force has equal and opposite reaction. Here in order to achieve this force the two drones need to exert the same force in downward direction and push the container.
In case 2: It is similar but you've to notice that the force exerted on the container thus increasing the total mass to 2Mg and the more the force the more the mass. And finally it creates a deformation.
This earlier discussion says that, according to Newtonian mechanics the netforce exerted by an internal system is equal to zero. And the net work done by internal forces is zero provided that they are not doing any deformation in the rigid body.
On simple analogy you cannot stop a bus from pushing the back of a bus from inside.