This looks to be challenging. As you mentioned you will not make the last Orange Line departure. The next best bet is to get to Piazzale Roma, most likely by taxi. From here the lines that stop at dell’ Orto, which is the closest terminal to your hotel, 4.1 and 5.1, don’t look to run that late. The Vaporetto does have a Night Line that stops at the Marcuola Casino terminal, and you would have to walk from there. Just be sure to get accurate walking directions.
The only other option, which I hesitate to mention is a private water taxi. They are very expensive, especially at the hour you will need them. I would grab a taxi at Marco Polo and get to Piazzale Roma. From there take the N Line to Marcuola Casino Terminal and then walk. With good walking directions shouldn’t be more than 15-20 minutes. Just pack light as you will have a number of bridges to cross. Good luck, this is all part of the adventure of visiting Venice.