^ Wow. How long did it take for that to go through?
Using 1 sat/vbyte could take months before it will be confirmed, it is not advisable for now. Even, using 5 sat/vbyte were luckily confirmed today since more than a month ago. Although, you can set such low fee if you want to consolidate your input, but make sure the transaction supoorts replace-by-fee, so you will be able to pump the fee in case of stuck transaction.
Also what is the input vs output thing on there? Sorry noobness here.
Assuming Mr A, B and C sent you 1 btc, 2 btc and 4 btc to your wallet address respectively, if you want to send the whole bitcoin to a friend, it will have 3 inputs, which are the number of times you received the whole btc you want to send irrespective of the number of addresses used to receive it. 1 output, because you send the whole btc to a friend and no change address.
Assuming you have 1 input, like only Mr A sent you 1.5 btc, if you want to send 1 btc to a friend, that means your wallet will send 1 btc to your friend and 0.5 btc to a change adddress (address on your wallet). This transaction have 1 input because you are sending btc from a transaction with a single received transaction (1.5 btc) from Mr A which can be used and remain change. 2 outputs because your wallet send to a friend and to a change address.
Transactions do not remain stuck for eternity. They either get confirmed or get dropped from the mempool after which you may spend them again.
Transaction can remain in the mempool for months, especially if the wallet is synchronizing with the blockchain frequently, this will make the wallet to automatically rebroadcast the transaction. The best is to just enable replace-by-fee before broadcasting the transaction at all, so it can be used in case of stuck transaction. Normally, it is 14 days mempool might drop transactions, but possibly not all the mempools will drop it, while some will take it up as the wallet automatically rebroadcasting the transaction. There are cases of transactions that will remain stuck for months in mempool, and also are cases a dropped transaction will still be confirmed later, this second case is the reason people are advised to spend the same input if a transaction has been dropped from mempool. But, the best advice is to never think transaction will be dropped from mempool because it can be so frustrating if someone is experiencing stuck transaction that do not support replace-by-fee.