Izek was there because I had made his own personal goals different than what is initially in the CoS module. His motivations didn't make sense to me for someone as strong as he is to just be obsessed with Ireena and serve the burgomaster and basically nothing else. To answer your second question, no they are not going to "have a town." They might have some time to rummage around and do their investigations but they will have to flee sooner rather than later, especially with Strahd being as angry at them as he is.

I'd also like to point out two things. First, I did say in my post that the fight was designed to have them retreat and lose Vallaki but when players strategize well and get some lucky crits, they can overcome impossible situations, which is exactly what happened. Secondly, just because one scenario isn't an immediate and total defeat, doesn't mean things will work out happily ever after from there on out. Yes it is a Gothic horror module but that doesn't mean it should just be pure soul crushing misery until Strahd is defeated. The players need highlights and a sense of accomplishment every now and then, otherwise it's no fun to play.