I have found I can use a stem a cm longer if I raise it another 1/2 cm so I wouldn't sweat the difference.
Different philosophies here on seat height. I am a fan of knee bend and ride a lower seat than many. For me it works. It sounds to me like both of these fitters suggested same bike and almost the same parts. A great start. If I were you, I'd leave the steerer long and start with either the 100 or 110 (if the bike comes with one of those, that one), space it as suggested. Set the seat toward the higher of the two. Seat setback to the fitter of the stem you went with.
Now ride. First, mark all your settings with either measurements on paper of tape. Bring the wrenches. Every three weeks, drop the seat 3mm (1/8"). Keep doing this until it is obvious "this is too low!" after a week or two. Go back to the last setting.
Also bring the wrenches for your brake levers and handlebars. (Consider your first bar tape sacrificial.) I like to use the cloth tape with adhesive. Wrapped from the bottom, unwrapping, moving the levers and rewrapping is easy, even on rides.) Adjust HB rotation and lever position so they fit perfect, both going uphill and all day on the flat. Good in the drops upwind.
Fit evolves. No fitter can get you "the" position right off. You will change. Sounds like both fitters got you into the same ballpark. Going back to one for the final fine tune is probably good, but it won't be the final answer and that's not his fault. You have to ride, put in the time to get your body to adopt and observe what your body and bike need.
Priorities, in order - seat height and tilt. Seat setback. Now - overall "reach". ("Reach" in quotations because stem length and height both affect how far the handlebars are from your shoulders, the dimension that matters. For now, shuffling spacers is far easier.) Tweak HB rotation (and perhaps look at handlebar shape, width, drop and reach if it doesn't seem natural), brake lever location (and angle in - straight ahead isn't the best for everybody and not me).
And relax! This is fun. And it goes on forever! My fit journey started almost 50 years ago (after years of riding bikes that didn't fit). Oh, on seat height, I started way too high. The vets in my club worked on me to bring it down. By my third year racing it was down a lot but over the next 40 years, it came down more. I haven't measured knee bend but I'm probably at the second fitter's angle.