Sort-of and No. The break booster retains vacuum for quite a long period of time. Then again, I rarely need to REALLY use the brakes... so for all I know, It's not working very well... I usually bump-start my engine before a stop and glide until then, so I guess I'll need to do some tests on that!
As for Power Steering, without an engine turning the pump, it simply will require some good muscle... unless you are electric power steering (seems most newer cars are heading that way). For my car specifically, I converted my rack to a manual rack anyways, which is noticeably better than the lines looped.