hey @nikita - ty for these questions.
1/ The implications of (1) is that given the community signaling support for the proposed on-chain governance implementation, we will share all relevant reports (e.g. finalized audit, gas reports) and anything else that the community would like to know about the smart contracts we developed and that we will deploy the contracts onto mainnet. Included in the development process is thorough end to end integration and migration tests to ensure that everything functions properly. I’m not sure if I know what second and third order effects you may be referring to - if you could name some examples that you suspect could apply that would be helpful for me 
2/ The key mechanism that we will provide to assist with the migration period is a revamped Governance Portal UI that tokenholders can go to to unstake from the current governance system and activate their ZRX for the new governance system if they choose to opt-in. We plan to make a modification in the related proposal (New 0x Protocol Website — Open Application) to explicitly call out that a new governance portal is within this scope of work.
3/ The audit is being finalized this week and we will share the report out as soon as that is done! While we are seeing approval prior to the audit being available for review, we believe that the transition steps proposed, particularly with the migration period and future vote that would formally switch ownership of 0x Protocol to a new governance system gives the community ample opportunities to signal their support/disagreement with the system and that this vote does not, in any way bind the community to on-chain governance.