"this is in Manhattan and I have no idea what the logistics are of getting demo done there are like and what disposal costs are " yes it's a lot of money- but perhaps you shouldn't weigh in until you've had a chance to park your truck in Manhattan, then wait on the service elevator or take the stairs, then wait on your tradesman to show up and find his parking, then pay for both, the actually demo the stuff and cart it out one trash can at a time and then fill up that truck and send it out to Jersey or Conn. for disposal as there just aren't many places on the little island that take busted up tubs and broken tile. You'll also need to markup these services and add a profit to the costs if you're running a business, so this stuff adds up quick ! This is EXACTLY why most businesses don't itemize costs, it simply invites discord because I'm sure anyone with an internet connection can find a cheaper price on a shovel or Moen faucet or laborer to cart out trash. You are paying for MANAGEMENT and expertise - not just a pretty faucet or trash removal and everyone want to make a PROFIT along the way.

A bumpout will still need to transfer the load carried by that wall, which will still need a beam. It can be an invisible beam in the attic or one hanging down into the space. Even though you've done the electrical upgrades to the panel, a new kitchen still requires a lot of wire to be run for dedicated circuits as well plumbing changes for the bumpout, HVAC---which would also include creating ventilation. The biggest determinant of construction pricing is location, which you have not given. And the biggest cost of any addition is in the first few feet of it. You have to tie the old to the new. Going larger is actually less costly per square foot because the cheaper space average out with the more expensive spaces. The kitchen is the most expensive room in the home to renovate. And you just took off the cheaper rooms from the previous project. I would not expect this small addition to save that much cost. Where it will save would be the fact that you aren't adding any basement area. Even though your project has been basically cut in half, I wouldn't expect the pricing to be cut in half. More like 5/8 to 3/4 of the original quote.

I agree with one of your options. If it will work, I would remove the cabs over the range, install a killer ModernAire (pricey, but my choice) or Ventahood in that space (no cabs or anything except the hood and encased upward pipe to the ceiling), and vent out to the left through the ceiling if at all possible. Use the biggest possible duct, the fewest possible turns, and a powerful outside blower. This will be expensive, but probably the best bet for good ventilation required for a powerful range and extensive cooking. And a beautiful backsplash above the cooktop or range to accent the whole thing. I am assuming you like to cook and will NEED a good exhaust. Then it is worth it. One caution: I was able to vent a 1200 cfm ModernAire hood straight out an exterior wall that borders our deck. Some have warned that a powerful exterior motor venting into an area used for outdoor living is a problem. We have no problems with ours since our outside dining area is slightly to one side, but I can see the shrubbery ten feet from the exhaust blowing about when the motor is running on high. Wouldn't be pleasant if we ate in that path. I agree that I would be careful about deciding to remove the existing cabinets. I gather you planning a significant remodel--perhaps new countertops as well as the new appliances and perhaps a new floor ? And a new backsplash. This will make a tremendous difference. Do let us know what you find out from the professionals who come to look at the situation. I certainly agree with those who do not think the multiple turns required to go out through the garage will work. And, as you know, you REALLY do not want a down vent.

I did this last year and paid close to $9/sf for demolition, new 6” thick slab reinforced with #4 bars 18” o/c. I live in Dallas, Texas, and that was the going rate at the time.