I found the answer to most of my questions here:

https://bitcoinarmory.com/download/troubleshooting/

My only remaining questions is:

When I cleared unconfirmed transactions (the 0.191 transaction was cleared), does that mean than the unconfirmed transaction is cleared also from the bitcoin network (cleared from miners queue)?

When I searched for the tx id on blockchain.info a few days ago, I got no results, which I take to mean that the transaction never got broadcast, nor did the transaction get subsequently broadcast on restarts of Armory. From what I can gather, this sounds like an issue between Armory and QT.

Perhaps I'll try the exact same transaction again and see what happens.

Thanks!