Haha, as a fellow Istrijan I agree with you on the differences in regional swears between Istrians and other Croats. This swears are also some of those that I use and I think you described the use well, as in these are tolerated around "family table". Usually I use combination of Porco/a (pig) + relevant religious icon pronounced in a badly Italian accent when properly upset.

p.s- sritno Novo Lito (using my father side ikavica, found in Karojba town region)