According to this map Croatia would become independent, but the status of Slovenia is less obvious, the map portrays it as part of the Austrian Duchy of Carniola, so it could either gain independence or remain part of Austria. Maybe they would have a referendum among the population of Carniola to stay in Austria or form a new country.
That being said, the borders weren’t implemented to look like this because Great Britain overpromised land to both nations to keep them happy and ready to fight for them against the Germans. So who knows what would happen ? They could gain more or less land.
And American president Woodrow Wilson’s 14 points would again be forgotten and Croatia/Slovenia aren’t really guaranteed a promise of self determination.