LTC1775 Buck converter component question
Are these two good choices with regards to the output current or they are overkill?


Use LT powercad (almost all linears DC DC conveters are there) to find optimal components, it is much easier to use and quicker (I'd run this design through myself but haven't the time).


  Should i attach a flyback diode across the output incase I have an
  inductive load like a motor?


Yes, you may also want to consider a filter, the DC DC compensation loop may also present problems from the inductance of the motor. Extra capacitance\filtering may be advantageous with a motor. Because the motor impdeance is hard to determine (and for most motors non-linear) it may require experimentation to get the right compensation\filtering and to avoid voltage dropouts. 


  Are the Cin and Cout capacitors adequate? Based on datasheet formulas our output voltage ripple is supposedly ~60mv but the
  simulation only shows ~10mv


You have a fixed load, switch the load in the simulation to determine if it really is adaquate (unless your load really is fixed).