First, FedEx did not knock or ring the bell when it was delivered. I found it the next morning sitting outside.
The part number 6, captive nut, broke during tightening. 

Can this part or part set be replaced?

About 7 months after receiving this item, the bottom of the drawer fell out. I tried to fix it; but, because it is flakeboard the wood just crumbled. I also realized the bottom was made of a very flexible thin piece of masonite (or similar) which explained why the bottom fell out.

I'm not sure replacing the drawer would solve the problem as it appears to be a poor design. I worry that other parts of the item will show similar flaws.

I wish I had known before purchasing as I would not have bought it.

Needless to say I will not be purchasing from wayfair again.