Pooks, I think practicing in a parking lot is a great idea. Mtbikers do skills training drills all the time while roadies neglect it. Your list of drills is good.
Slow race a friend with your feet unclipped. Last one across the line wins. You'll learn great low speed balance and can eventually learn a trackstand. This means you can slow way down when approaching something (like a traffic light or foot traffic) and learn to balance for just a split second while you determine whether to stop or turn or just delay your progress.
Also, learn the high speed emergency stopping technique. Maybe someone will have a link to better directions but, essentially, platform your pedals (at 9 and 3), straighten your arms and throw your butt off the back of the bike and apply both brakes hard. DO NOT TURN IN THIS MANUEVER. You ever watch a sprint "throw" his bike at the line for the win, butt back and stretched way out low over the bike? It is the same manuever but you are adding the braking. Throwing your butt back means you won't go over the bars in the rapid deceleration. This skill can save you from slamming into something like a suddenly opened car door or a child running into your path. It is one of the most important skills for a cyclist to have because it can save your life - the ability to go from fast to stopped in a split second. Having the slow speed skill will help you with stopping and not falling over with this fast manuever.
If you have a nice dirt lot or grassy area - even better practice area.
Frends know gud humors when dey is hear it. ~ Da Crockydiles of ZZE.