Bitfinex isn't the party in question here. Unless Jump has their own coin they can mint out of thin air and convince people to buy for Ether, or are able to convince any of the other main tokens to mint for them, this scenario isn't even plausible.
None of this is remotely accurate and nobody minted Solana. They minted tokens that no longer exist ON Solana. $320 was spent in ETH - a plenty liquid asset that they have that much less of and that lowers the total value of their holdings by that much.
I'm not sure about the state of things in 2017, but in 2022 Coinbase will convert your USDT into USD and let you withdraw it. I have a lot of trouble believing the likes of Coinbase have either not done serious diligence on Tether or are willing to perpetuate what would probably be the largest ponzi scheme in world history by a long shot. Coinbase is a public company with executives that are not eager to go to prison, not a bunch of anons with frog avatars.
