What is the serial and model #? That will determine what emblems or decals it would need. Also if it is a Wizard, Sears,Elgin or Scott, Mcculloch. These are 64 an seem later Emblems...
I am not ripping on you. With the price of your EMM and the parts you just bought you exceeded the value of the motor. That is just a fact. Don't be mad because your motor went obsolete in less than 5 yrs of being manufactured. Your mechanic should be able to tell you which pump. Why don't you...
The $185 one is a Chinese knockoff. The $500 is the OEM one and the one I would purchase. Or you can convert it to a premix motor with a $100 pump. As far as the prop goes look on the hub for either the size or parts #.
So instead of having it scanned and getting the specific code, you decided to load the parts cannon. Good luck with that approach. If your mechanic worked on it why did he not tell you why part was throwing the code. Everything you just bought probably exceeded the value of the motor.
Do not buy the cheap Chinese one off of eBay unless you plan on using it as a pre mix pump. Ditto with the used one. The no oil flow sensor is in the pump, so if the pump is still moving o there will be no alarm.
That piece looks like the bracket that holds a shifter cable for a remote control. I believe that motor uses friction to hold it up. If it doesn't give us a pic between the brackets with the motor up. Might be a bracket missing or broken.
Which 150 do you have? I am going to guess it's a looper. Check for warped float bowls especially if they are plastic. Check the mounting surface of the carb for being warped.