The complexity is definitely adding to the job (but not 50K imho). That said, design work is expensive and what you might consider doing is doing a design separately and bringing that to a good contractor. You may also want to part out the plumbing work as well. Not 50k worth, but you're definitely paying to having all those types of professionals under one "roof".

You can probably get a few more quotes for less, but if you want a hands-off approach like this, you're going to pay for it. The perk is you don't have to deal with any of the permitting and other bullshit that might fit between the cracks of diff contractors.

My advice (fwiw), is probably to hire a designer who can do that work and also give you a rough price. Keep in mind, designers like to upsell finishes because, like all people, they prefer to work with superior products and produce a superior product. Also, I find designers to be OKAY at pricing, but not very good and understanding the market itself - so the price you might get from then will be VERY rough.

After you get the design, I'd shop it around to a GC.