Few issues to address here, as you may have suspected there is no "easy answer" to your question(s), I see 3 questions in your post. Since you did not state what type of facility this is I am assuming this is a commercial or industrial facility in the USA with employees.
First, training. The training requirements found in the NFPA 70E are the same as the OSHA requirements of subparts S and R, just with a little more detail such as documentation, refresher training, non-qualified training, etc..... So yes training is required directly from the OSHA standards.
Arc flash study, actually you are not required to do an arc flash study, however per the NEC you are required to label your equipment with the hazards (110.16) to do that for the arc flash hazards you can either use the tables in the 70E or conduct an arc flash study. However, to use the tables you have to do some engineering analysis to see if the tables can be applied such as available fault current and clearing times of OCPD's. Also, the tables are in many cases very conservative so employees often end up wearing more PPE which can be difficult to work in and increase costs for PPE purchasing, care, and repair/replacement.
Now the big question, OSHA complaince, this paper sums it all up very well.
http://www.iamu.org/default page links/IAMU Article - NFPA 70E Compliance.pdf
