@jazzies maybe @bixo can help answer your questions. I had a problem with a pending iota transaction from bitfinex and I was assured by someone from the iota slack channel that my transaction was not lost either way. Ultimately I had to put in a ticket with bitfinex and it took a month for them to contact me back but when they did they refunded my iota.
Also, bitfinex has very detailed instructions on how to send iota to a wallet and the transaction can be viewed on tangler.org. From this website I was able to take a screenshot of how the transaction did not complete and a picture of my account balance being zero. If I can find these links I will add them. The second time I transferred iota using the instructions and I did not have an issue. Good luck!