I don't think the signatories believe they are achievable by any negotiation, Keith, and not the day (or perhaps the fortnight) before an agreed position has to be announced. It seems to be more about positioning than actually achieving anything more concrete.

For example if Ireland/the EU needs to be convinced that there is some mechanism for harmonised regulation across the border to prevent a hard border I would be astonished if they could agree to no regulations after 2019 having an effect.   The same is true for EU residents in the UK and the role of the ECJ.

So this all 'hard Brexit', so in effect no agreement. Which does require a hard border, in most people's opinion, though I accept you don't think so. And I believe that is the worst possible deal - again, I know you don't agree.