Coming along nicely!
Hopefully you'll find your speed sensor in the box of electrical bits, maybe?
It's a round white plastic 'thingy' with two prongs, one longer than the other. And a metal plate to hold in the hole in the diff.
I mounted my steering rack with some tubes and bolts supplied by Marlin like this....
Steering Column by
marlinpeter, on Flickr
It's to drop the steering wheel down a bit to give a better driving position. (but it was a subject of much debate amongst builders on the forum a few years ago!) You may have the tubes in your box-o-bits?