UK leaves EU?

[Mich the Tester]

You should know that you can't have dual citizenship in NL.

Yes you can, if you're married to a Dutch citizen.

[Mich the Tester]

The freedom of movement agreement applies to the European Economic Area and that is not same thing as the European Union. It's EU + EFTA (Iceland, Liechtenstein and Norway) + Switzerland. There is a Europe outside of the EU.

If the UK leaves the EU it may rejoin EFTA. It may even come to a bilateral agreement with the EU regarding freedom of movement just like the Swiss have. Either way, British people in Europe are not going to be loaded into cattle trucks for resettlement north of Calais.

You can all hold off on the dual citizenship application for the time being.

Ah yes, but 'may rejoin EFTA' and 'may even come to a bilateral agreement' are not really convincing enough for people whose families are then spread across EU and non-EU countries.