1. possession is 1/10ths of the law, lol thief or not there should be a standard or code which unfortunately the new age failed to adapt unfortunately
aside from that and fact that onsite is only possible if same country and such, I do not really see any other issues with your points.
Online credentials are needed in most cases for some it may be a way of assurance while some jobs are just not possible with out.
Yes either side can try pulling a fast one but thats when certain principles and ethics are supposed to play a role.
As far as the Oa , USAx2 and CU, I am able to work with all those and the Percentages that u stated are not really an issue depending on specific job , as they are not far off from my usual splits. If interested or have any questions do feel free to reach out.