MOSFET - shorting the gate and source
If the gate is tied low, then the mosfet won't turn on (like the two lower mosfets in your circuit) It will then function like a really high value resistor, and would be pretty pointless to use a mosfet like this in a circuit. Modern mosfets also have reverse current protection with a body diode (some have this left out) 


  EDIT: Additional question, one more question is that if you look at
  the MOSFET on the primary side it has a diode connected parallel to
  it(i was told that this is the body diode and not an external diode),
  but on the secondary side the ideal NMOS doesnt have the body diode
  shown. Why is that?


You need to check the mosfet spice model to see if it has a built in diode into the model. In spice it is all up to you to know what your modeling, if you really wanted to you could put in any circuit file tied to what looks like a mosfet.