Oh!Great is so inconsistent with his work, I wouldn't worry too much about the colour. In the anime it is light blue, however, the anime can be quite inaccurate, such as with Agito/Akito.
I'm not sure how to help with the kanji, I apologize.
The two wheeled roller baldes can be obtained throgh eBay, however, the wheels are rather small on all of the ones I've seen. There's a tutorial here
and a few on YouTube if you make an "Air Treck" search, and modify the tutorials to your need. I know this member, Raknorak
made Kazu's Air Trecks, so you can probably PM them for assistance.