Rome2Rio suggests a 4h50m bus journey from Agrigento to Siracusa via Catania as your cheapest and fastest option:
Buses run several times a day and are operated by SAIS Trasporti, whose website details the itineraries and costs of all the tickets.
Alternatively, you can choose a 5h regional train journey via Caltanissetta. This itinerary is available once ...
The official website of Deutsche Bahn lists the current interruptions due to corona (only in german, trying to change the language to english took me back to the main page):
According to this site, several trains between Germany and Austria have been cancelled, including the NightJet, but I assume ...
If you wish to use the Deutsche Bahn to cross the border to Austria, you should check the Deutsche Bahn site for known train interruptions
no trains or busses to Tirol (western Austria)
at present (2020-03-19) none for other areas inside Austria as final destination
Assume that this may change at any time.
Check eligibility to enter Austria
at the ...
Deutsche Bahn allows you to cancel you travel if the reason for travel becomes obsolete - this includes quarantine at the destination. This should allow you to cancel if the tickets are DB tickets. Otherwise the conditions of the other operators will apply. Do you may have to cancel the Italian tickets through Trenitalia.
Italian long distance train tickets work along a completely different system then German train tickets. Italian trains have passenger manifests. German trains don't. That is why you cannot find any Italian PRNs in the German system. Deutsche Bahn does not use PNRs at all (as they do not care the slightest bit about who is on their trains...)
You could try ...