I would just like to confirm, that recovering litecoins from bitcoin multisig address is possible. I tried and it worked. But most importantly, Bitfinex staff worked on that problem too and succesfully recovered my over 4000$ worth litecoins.
Thank you Bitfinex for putting all the effort.
So guys, be careful, when sending Litecoins around. Litecoins can be transfered to bitcoin multisig addresses. But if you will send them to address, that you don't own keys for, then you are at mercy of people who do have the keys. In case of honest exchanges, they will be able to return the coins, but returning them does require additional work for them. So try not to do same mistake that I did. In case you do, I can confirm it is possible to recover them.