How much average power delivered to each antenna?
In comments you said,


  I know that the two loads simplify to 75/2. And that from there, the input impedance equals that of the new load.


So you know the effective impedance of the whole load network.

From that you can find the power delivered to the network. The only place in the network where this power can be absorbed is in the loads.

Now, looking at the symmetry of the problem, is there any reason to believe that antenna 1 receives more power than antenna 2, or vice versa?