I've read that an experienced auto bodyman can draw that cutting edge up level by applying a torch to the bowed part and letting it shrink when it cools.
My cutting edge is straight but the top is well, 'experienced' after 30 years of abuse. I don't see any reason to straighten the top on either yours or mine, the dirt won't fall out or anything. Mine has a trailer ball in the center. I recommend adding one.
I think it is a good idea to add hooks at the outer corners, but I don't think reinforcement is needed for either the hooks or the trailer ball, and a new bar across there just makes the tractor more nose heavy for no advantage.
On mine I added simple hooks, ('cold shuts' for splicing chain) at four points. Now I can drive around with a suspended load without it swinging around. These little hooks are sufficient for the 800 (??) lbs these things will lift safely.
This attached photo illustrates some forks I made, but it also shows the 'cold shut' hooks I'm describing. They are simply bolted through existing holes, and are free to swing around. They are also a good place to carry chain.
http://www.nettractortalk.com/forums/attachment.php?attachmentid=276&d=1185757849