Visiting Salzburg on August 15th – shops, restaurants & transport?

Hi! We’re planning to visit Salzburg tomorrow, August 15th, but we just found out that it’s a public holiday.
Will most shops, cafés and restaurants in the city centre still be open because Salzburg is a tourist city?
Also, does anyone know if public transport in Salzburg will run normally on the holiday? And we’re planning to take the RE5 from Munich - does it run normally on August 15th, or are there any changes/cancellations?