First Uke Project

A little background...
I have no experience with instrument fabrication AT ALL. However, I have an old Wabash Ukulele that I found in my friends garage. There are no tuning machines, there isn't a bridge, and the nut is chipped off completely on one side. He let me have it; I ordered "Ping Geared Tuning Machines" off of amazon, a bridge with a bone saddle off ebay, and a blank bone nut also off ebay.
Tuners: http://www.amazon.com/Ping-Ukulele-Geared-Machines-Tuners/dp/B000EEHI0W
Nut: http://www.ebay.com/itm/Ukulele-Nut...172?pt=Guitar_Accessories&hash=item1c296092c4
Bridge: http://www.ebay.com/itm/160843104818?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649

Now for the questions...
1. The bridge I ordered has holes in the top that are drilled straight through to the bottom [and are quite tiny], I was under the impression that they were for the strings until I received it. What are these holes for? Do I need to cut my own notches for the strings? [obviously not a tie-bridge]

2. The bridge's saddle also is also squared at the top, I do not know much about compensating the saddle [the thought of lining the bridge up so that the intonation is even close seems daunting to me] but it seem to me like I will need to sand it myself?

3. How do I sand and shape the nut?

4. Less related and less important, but, if I wanted to put a pickup in it on a super-low budget, is there anything that is really cheap but still worth my time?

Thank you in advance for anyone trying to help! Just tell me if I need more information [may be able to get pictures, but not sure yet]

The bridge must be a through-hole type. You drill through the top. The string ends go inside the uke and get tied with a knot so they don't pull back through. Just a different style bridge.

for compensation look here... http://www.stewmac.com/FretCalculator You should round over the top of the saddle. To get the uke's scale length measure from the front of the nut to the middle of the 12th fret and double it.

Bone sands and shapes pretty easily. Cut it to length with a fine tooth saw or hack saw. Shape it with a file or sand paper. Lay your sandpaper on a flat surface and go to it. Watch out....the corners can get very sharp as you sand. A set of torch tip files from Home Depot will put the grooves for the strings. (slow method but cheap)