As much as I understand the Ledger wallet Bitcoin App should prevent me sending unconfirmed Bitcoins, am I right?
By default, I believe the minimum number of confirmations to spend from the "Ledger Wallet Bitcoin" is supposed to be 1. There is a setting in the "Settings -> Coin" menu... Why it chose the unconfirmed coin, I don't know?!?? 
You might need to contact Ledger Support and ask them why it spent an unconfirmed input. They won't be able to fix your particular problem, but it could prevent it occurring in the future if it is a genuine bug and that setting isn't working the way it should.
As for your transactions, they don't use super low fees... 100+ and 200+... so there is a good chance, that given enough time they'll confirm. You could also try various accelerator services like ViaBTC etc.
