Most 42" decks will have 2 x 21.25" blades
Most 46" decks will have 3 blades, either 3 x 15.5" ones or 1 short & 2 long blades
Blade lengths may be +/- 1/2" different to the above depending upon the spindle positions but close enough .
Within a brand most decks will interchange
As for the steering, there is a bush at the bottom of the steering shaft that is supposed to be oiled if metal or periodically replaced if plastic .
There is also a bush in the fan gear that needs oiling & replacing
\You will se them as parts # 22 & # 58 in the linked page below.
This is not your particular mower but the parts are the same & the diagram is a lot clearer than the one Sears use on their web page.
Steering gear