If I had to spend a year on a Thruster I'd get front brake, pedals and saddle right away, but I already know what saddle I like. For an absolute noob I'd just go front brake and pedals. Then other parts as they fail.
I dunno if Promax RC 470 has the reach needed or not, but maybe.
Assuming you're running freewheel I'd just get some BMX platforms. Make sure you get the right ones 1/2, 9/16.
Thruster talk always heats up in the summer, don't it?