The lower cowl is sandwiched between the exhaust tower and the powerhead. You will have to remove the powerhead with tiller handle I believe to separate the lower cowl from the rest of the motor. You will have to disconnect the shift linkage from the tiller handle to the shift lever as well. Take pics as you take it apart. I wouldn’t even take it that far unless you deem it absolutely necessary.

For the prop removal you need to straighten the tabs on that tab washer ahead of the cone nut. Once the tabs clear the notches in the cone nut base it will spin off. You can then pull the prop off the shaft. There may be a spacer washer under that tab washer as well.