Moldova's Russian minority is mainly in Transnistria, which is east of the river Dniester. The Romanians only annexed territory up to the river, meaning that Transnistria would have been in the Soviet Union. Moldova's Russian minority west of the Dniester is scattered around the north, and is too dispersed to organise a secessionist movement.Moldova has a minority Russian population OTL with a corrupt (even by local standards) little breakaway republic and they weren't all Stalin era transplants.
As I have said before on Austria-Hungary threads, Trieste was Italian in 1914 but its hinterland wasn't and, as better medical care and mechanized farming kick in, along with Trieste being Austria - Slovenia's principal port ( and thus not a dying city like OTL) there will be more Austrians, Slovenes and probably Croats in Trieste than Italians ( who will be the old city families complaining about the blow ins).
As for Trieste, only P-M knows the answer, but it is likely that an external power stepped in to ensure that Austria kept Trieste as a compromise, with Gorizia to ensure a land connection to the rest of Austria. Since Yugoslavia does not exist ITTL, in a shooting match or full-fledged war, I have a hard time seeing Slovenia or Croatia keep any disputed territory from Italian ambitions. They're simply not strong enough on their own.