Can't answer long now...but, take your time with this(and it will take some time)don't rush it, you need an absolutely complete plan for a builder even to get a quote.I have to come up with a design to tell my builder guy,
This is where you'll get drenched getting that sip out of the fire hose,
there's a lot of details, but it will be worth it to take your time before pulling the trigger.