I take it you’re renting a car. The drive from Zurich to Ljubljana is 7.5 hours non-stop, from Munich Airport it’s 5 hours non-stop. Doing it while jet lagged is not a good idea. Add another 2.5 hours to driving times when setting off from Plitvice Lakes on the 12th plus any possible border delays and pit stops. I hope you are planning your flight back on the 13th or at least late on the 12th.
You’re left with five full days to do six very full sightseeing days without spending any time in Ljubljana itself, so some significant adjustments are needed.
The Karst day itinerary is impossible. Postojna and Skocjan can only be visited on two-hour guided tours, which in October are held six and four times daily, respectively. Planina Cave can only be seen on a 4-hour tour that has to be arranged in advance, provided it isn’t flooded. Add everything else on your list and you’ll find you simply cannot fit it all into one day. As the previous poster mentioned, it’s a similar story for Istria.
You can make it an enjoyable trip, but you have to amend your plans. For starters, fly into Venice, Ljubljana or Zagreb to eliminate the lengthy full-day drives on the 6th and 12th, giving you one to two half days that can be spent recovering from jet lag or exploring Ljubljana. Then eliminate one to two full areas from your itinerary and pare down your plans for some other areas. Choose either the Postojna or Skocjan Cave in the Karst (Planina can be enjoyed from the outside and is a quick stop if you’re not entering), eliminate Logarska dolina and skip Pula would be my suggestion, although Istria would likely need further adjustments. It will still be rushed, but at least more manageable.
Consider the weather, too. At least one of your five days is likely to be rainy. If you’re unlucky all five days could be gloomy. The sun will set at around 6pm, further limiting available outdoor sightseeing time. Even pared down, your itinerary leaves no room for inclement weather, so be prepared to have to change plans at the last minute. The good thing is that you’re based in Ljubljana and can switch around day trips on the fly (for example the caves are the same whether it’s raining or sunny outside), but do pay attention to the weather forecast.