If it is the spindles you are greasing from the side, the grease does nothing but fill a void. If the grease nipple is on top, it likely unscrews when it hits the frame when deck is raised.
I always put on the Shrink Sleeve FIRST! Usually Crimp/Solder then cover with Permatex Aircraft Gasket cement, allow to dry and then shrink on Insulation sleeve after trimming any burnt wire insulation. There are many ways to do this.
It appears to be the Stud that holds on the Electric Clutch to me. There should also be a key. Have you checked rear axle/wheel bolts, the centre one, some with keys? Idler pulley may be missing a stud.
Remove and clean the Spark Plug. Spray it with Brake or Carb cleaner. Let dry and reinstall.
Spray a bit of 'Quick Start' into the Air Breather with Choke OPEN and pull several times. Then try with choke on slightly.
First try lubricating the Bendix (spring return) drive. Grooves in shaft. . When you try to start, the gear should spin out to the end and starter rotate freely. Release the key and the bendix spring should return it to park.
Check to see if you have not pinched off a fuel line during repairs and that you do have fuel.
After leaving it sit for 20 min, give it a shot of Quick Start and pull the rope, choke mostly open.
I have an X320 and I love the way it cuts. 4" is way too high for me in Southern ON. I have it set so the bogey wheels barely touch/rotate. You might look and under deck adjustments to Deck Hangers.