I couldn't hazard a guess. I'm not a plumber, but I'm guessing you're in better shape than someone with a 100 year old house, where anytime you expose anything you risk exposing a whole bunch of WTF. Like Oh look, knob and tube, I guess we're rewiring the house now.

Judging from my current building project I'm guessing if you get lucky and get a remnant to extend the countertop that would probably be about $6-700 installed.

Matching the floor could be tricky, but maybe you could make the decision to change the floor in the dining room (even if you get a similar wood and change the direction or put down some sort of different wood to create a border to kind of hide it not matching exactly and use the pieces you remove to patch the area in the kitchen (probably just 1-3 boards depending on how wide your flooring is and how sloppy they were when they drilled) If your cabinetry isn't actually set on finished floor, that opens another can of worms.

You'll have to patch drywall in the basement, and hope that there isn't any ductwork or joist stuff in the way of where you want the sink to go eventually. If you want it to look decent, you'll probably have to repaint the basement ceiling after that's done. (at least until a wall or beam that drops down) Good paint is not that cheap, so lets say you do it yourself, and say 2-300 for paint depending on the size of your basement.

The plumbing parts aren't that expensive, but getting a plumber to do it is. Getting the granite uninstalled without damaging it is anotther tricky bit. Where is your seam? Is it on the corner or does the granite curve around the corner in a single piece? If so it's going to need to be cut.

Sometimes removing a sink could damage it, so you might have to replace your sink, and if you can't get the same model you might have to find one with approximately the same cutout, or if you can't find one, you might have to replace the whole sink section of your granite with a new slab, which would probably add another 500-1000. (sinks aren't cheap either)

Are you going to need new cabinetry for that 4 feet? Can you match what you have installed? Or you could do something like add a beverage fridge a kegerator or other under cabinet appliances and not need cabinetry for part of it, but appliances are expensive. You could possibly put open shelving there as well, but if you have pets or children that could be really complicated. (my cat would get on the shelves and knock everything on the floor) :)