What is the attitude of those NPCs? They should at least say they don't want to talk to you if it is negative, though...
Save first, then try moving stuff around them, sneak and try getting caught pickpocketing, or do some 'accidental' damage with a weapon or AoE spell effect. Does that start a conversation?
There was an uncmmon bug in the alpha with possibly not being able to talk to NPCs after a certain conversation at the end of the Black Cove. In that case, leaving town through the north or north east gates and returning could fix it.
Please email supportdos@larian.com, with a description of the problem and the report.zip file generated by the
D:OS support tool.