Looking at your build list I have a few suggestions.
Kcnc brake lever, 28 grams as compared to the 40 gram bombshell. The Kcnc has a nice shape and lots of reach adjustment for small hands, my son has been using it since he was 3.
Cable and housing, Aican Bungarus with Kcnc titanium cable, complete for a mini should be about 20-25 grams compared to the box at 74 grams.
Kcnc knife titanium pedals, 139 grams compared to aest at 170 grams.
Depending on budget and how crazy you want to get you could do some Alienation Anklebiters with Custom Tune 45/150 hubs and Pillar Xtra lite spokes. Even if you lace it fully spoked with 28 front and 28 rear spokes you'd end up at about 925 grams for the pair.
Tronix cranks will save some grams as well.
As for the 1" compression plug and cap, you don't need that, it's only for preload adjustment. You can adjust it with the stock setup and then remove everything and replace it with a carbon circle which weighs less than 1 gram, this will save you anywhere from 20-40 grams depending on what your current setup weighs. The carbon cover for the stem is easy to make in just a few minutes, if you want instructions just let me know.
I'm sure there's more weight to be saved if you post your full build list. I have a spread sheet that I use for calculating weights which is pretty thorough if you want a copy shoot me a message with your email.
Here's a sub 12 pound ProXL that I built for myself. http://fairwheelbikes.com/c/forums/topi ... est-proxl/