If you can get up to say 4.01 by the end of Monday, you'll get "instant" (after an hour or two) promotion & then get promoted post-midnight for being a D3.01.. meaning that effectively, for having 3 clean races, you'll go from being a R2.50 to a C2.01
No, because as well as the SR requirement, to go from D to C he also needs to have done four races or TTs in a series that counts towards his MPR, i.e. a D series (one of the GT Cup, Mustang Cup, or Skippies). You
can skip levels using Fast Track but you need to get your SR above 4 and then 'race up' (or timetrial up); as a Rookie, that means one of those series I just listed for the road license. Then from C you can go straight to A by getting to C4+ then 'racing up' in a B series for four or more events and getting to 4.99, so two iterations of fast track take you from C4.99 to B4+ and then from B4+ to A.