Hi, a warm welcome to the forum
Don,t worry about the IVA test, yes its tough but if you build within the boundries of the IVA manual then you shouldn,t have too many concerns, tho I,m sure you,ll receive as much help/info from the members of this forum to help you with your build. The IVA is there to ensure that we all build a safe car, which in the long run is good for everyone.
As for the reverse box, yes you do need a reverse when installing a bike engine, there are a few options available to achieve this, some expensive & some less so,
with the steering column, if you use a column from a donor such as the sierra as the book suggests then its more than likely that the column is of the collapsible type anyway,
Good luck with your build, & don,t forget..............its meant to be enjoyable,
cheers
andy