Good point about plaster from Kim. While it may not be the current style, it sure looks great. I'm not sure about price over there, but that would have been around $2K on ours.
Leaving out the salt water chlorinator might save about $1K, but it will be more work adding chlorinating liquid, and you'll pay the same amount of $ over the next 5 or so years. If you get an SWC, be sure it's the largest one in the brand you're planning.
With 14 jets in the spa, I would leave the spa jet booster pump in. You could switch to a single 3HP variable speed, but then you'll also want automation to run everything, so there wouldn't be short term cost savings. If automation is already included, then that might be an option. For your main circulation pump, definitely get a two speed as mentioned.
The heater could be left for later, but that would mean no hot tub for the time being.
You can leave the slide out for now, and just have your plumbing ready for the future.
A big dollar item might be your surrounding deck. There's lower cost and good looking finish options, or you might be able to leave a section for later. I don't know the rules for safety fencing there, but there's a wide price range for that as well.
Perhaps the most effective way to get a good price for finishing it is to provide a complete and specific, written, description of what you want done, and somehow explain what limited warranty you're able to live with. If I was a contractor, I'd be worried about unknowns, such as what happens if the pipes leak, what happens if if if, how easy you are to work with, all that sort of thing. For pool builders, they're figuring that stuff out as they're making the initial sale, but now it's in the middle. I would also express a willingness to be fit in over the winter, i.e. "I know you're busy and this is different for you, so I'm happy to be flexible with respect to your schedule, make sure your guys can get in and out easily, or anything else he thinks I can do to smooth the way. I'd also make sure he knows the permits won't cause him any hassle, and show him whatever is needed so he knows that's all OK.
What a lousy situation for you geez. :shaking: I hope you have some sort of efficient claims system there, or can sue the sunofagun. If it's blood from a stone, hopefully there's a way to at least scare the pants off him!