2 (rights of citizens and the payment required) of the 3 issues are very easy to solve.
The ball for those is squarely in the UK's court but the UK government is so scared of its own shadow (the Tory EU sceptics) and the Red Tops that they are unable/unwilling to grab those bulls by the horns.
The major 'monetary' bill bits are:
- Pensions of those who have accrued rights whilst working for the EU.
- Commitments agreed to as part of EU activity during the current EU budget's lifetime.
- Projects in which the UK wants to continue to participate and wants to continue to benefit from.
It would be my view that any reasonable person/entity breaking up a relationship midstream should just be big enough and face up to paying for those things. Let's face it, that is what the UK would expect if the shoe was on the other foot and according to the Brexiteers the UK will be such a thriving and successful economy that paying the bill will be easy and small fry.
Citizen's rights - do what you want with visas/borders etc what you like after the UK has left the EU but anyone who has moved before that should be able to stay where they want or return as they want.
The big issue will be the NI/ROI border.
I cannot see how that can be a soft border if the UK wants to 'control' its borders and there is no longer a custom union between the EU and UK.
If it becomes a hard border it will be very much big problem for the people living on the island with both the NI and ROI economies being affected adversely.