Is the following correct?:
If I received 5 XMR from Bob, then I wanted to send this 5 XMR to Alice.
Would I create a tx with the input as the 5 XMR from Bob with one output as 5 XMR to alice. Then look for another tx, fetch K inputs and outputs from that tx along with their public keys.
Then add those K inputs as inputs to my tx, along with the corresponding outputs for them. Because if we do not fetch the outputs, then inputs-outputs-fees != 0 and it would be rejected.
The tx is then signed with the ring signature using fetched keys + signer as the ring.
Interim Question: What is stopping me from fetching old inputs plus my own fresh input, then creating new outputs of my choosing, which spend the old inputs + my own? It would be valid since the keyImage I use will be the one for my new input, while the total would add up to my input + old inputs