Strangely enough, in the first photo you look a spitted image of my colleague and she is Kosovar Albanian from Besiana (maybe a bit prettier, joking:grin but also my family has quite a number of blond girls (and boys for that matter) and, when abroad, are often mistaken for Russians or Swedes. Your mom can pass for Albanian but your sister does not seem to have Balkanic features. Apart from that you look strikingly Slovak to me, not Nordic.
Albanian? Interesting, from my exp Albanians look very Southern, in terms of pigmentation and stature- close to Italians and Greeks.