My certification was in 2014, but I'll try it:
- AFAIK training is not mandatory but useful. But you'll need couple of years experience in administrating QV infrastructure to succeed
- yeap, 65% is minimum
- yes, those points are useful, (at least as I've done mine) you need lots of knowledge, not only about how it works, but also things like:
Where is this option in qmc? Tab1 or Tab2
Which logs you don't have in QVS? Audit/Session/Performance/Reload
So the only thing is really mandatory is experience in QV administration.
It's been over 3 years since I sat for the cert but I recollect spending time getting to know the QMC backward and forwards > know the functionality available in each tab for the different QV services. It may sound a little dry, but reading the Server/Publisher Reference Manual will help.
Hope this helps.