Whatever the issues, the problem with making decisions about how 'Brexit' will affect them is that we don't yet know which type of Brexit we'll end up with.
If it turns out to 'hard Brexit' then the UK will leave BOTH the European Union AND the European Economic Area. That will satisfy those who want to get rid of the 'free movement of citizens' which currently exists across the EEA but (because we'll also lose the right to unrestricted trade within the EEA) will potentially lead to massive job losses (with perhaps 5 to 8 million people unemployed) and the near-collapse of the UK economy. Under such circumstances house prices might fall dramatically (by perhaps as much as 50%).
However if we end up with 'soft Brexit', where the UK leaves the EU but remains within the EEA, then we'll be in a position similar to Norway, where we have to abide by the majority of EU rules (including the free movement of EEA citizens across borders) but have no right to vote on what those rules should be. That will infuriate those who wish to block immigration from within the EU/EEA but leave the UK free to trade with the rest of Europe without restrictions. That type of 'Brexit' is unlikely to affect the UK economy dramatically, so house prices would be largely unaffected.
My guess is that we'll either end up with 'soft Brexit' or a reconsideration of the whole issue but, until the 'soft v hard' decision is made nobody can really predict what might happen.