You asked for advice and here is mine: Modern building codes (and most old ones) require "emergency escape and rescue" openings from ALL sleeping rooms and habitable basements. All window manufacturers have a mark in their catalogs next to the windows that meet the most common requirement. Ground floor openings are allowed to be slightly smaller but it doesn't always translate into a smaller window size. The internet can be highly unreliable for code information because most codes are copyrighted and they also change every three years so you need to buy a copy of the version of the code used in your area and get any modifications from the local building department. As the property owner you will be responsible for meeting the building code and because you will not be using a licensed design professional to assure you of code compliance, you should not rely on any code information from anyone that you haven't personally verified in your copy of the code book. Please take this advice seriously. The next step is to find the window inside sash size from the rough opening size by subtracting about 3" from the RO height and 2" from the RO width. Obviously, you will not be able to use your narrow window concept for at least one window in each bedroom. Your designer will be able to help you modify the house design to accommodate this fact. I strongly recommend giving up the idea of aligning door and window heads unless, of course, they align by chance. Windows should be as high as possible in a wall to bring light deeper into a room. Never let standard door heights dictate where windows are placed; they serve entirely different purposes. Get the windows as high as you can. If a 4" head misalignment bothers you then use 7 ft doors. In old homes both grand and humble this was never an issue. I would recommend a 3-0 x 5-1 RO window with a sash opening of 2-10 x 4-10. The interior stool trim would be 2-2 high with 1-0 of wall above the window. The head opening would be 7-0 high (an excellent height IMHO) and enough above a 6-8 door head to look fine or you could use 7-0 doors. The only other choice would be a 2" wider window that is 4" shorter. I would raise the stool 4" to 2-6 (table height) for increased privacy and keep the window head the same for maximum light. Of course, you could align the doors and windows and keep the stool height at 2-2. Frankly, I would consider a window with a 30 glass width normal rather than "gargantuan". You might find a code compliant casement with a RO width of 2-4 wide. The hardware on some casement windows does not meet the building code emergency escape requirement so you sometimes have to specify the appropriate hardware option. I would take a look at it before ordering it. If you prefer the appearance of narrow windows I suspect you should be using casements anyway.

A sliding window would work in that size, should give over 8.5 square feet. Unless you can make the opening a little taller I don't think a casement will work. The slider would work best but it is not to hard to make the opening taller and it would only take an inch or so. You would have to use 2 Windows with a casement since max width is around 36"" . So 36" wide egress casement mulled to a 24" wide casement or deadlite.

I imagine that the expense of the grading, concrete, well, etc. will amount to a project of some significance. At that point, the window should only be a very fractional portion of the project/labor totals. If there is a good match to the profile in vinyl, that should be fine, but I can't imagine a different product really moving the needle much on the total price.

Basement Egress Window Requirements The bottom of the egress window opening can't exceed 44" from the finished floor. The minimum opening area of the egress window is 5.7 square feet. The minimum egress window opening height is 24" high. The minimum egress window opening is 20" wide. The egress window must have a glass area of not less than 8% of the total floor area of room(s) for which it is servicing, to allow the minimum amount of sufficient natural light. * The egress window must have an opening area of not less than 4% of the total floor area of room(s) for which it is servicing, to allow the minimum amount of natural ventilation. * * Multiple windows can be used to service a single area where one window does not meet these percentages of total floor area. As long as the totaled amounts from this combination of windows meet or exceed the 8% for natural light and 4% for natural ventilation. Egress Window Wells Egress window wells are required where the bottom of the egress window is below ground level. The egress well must not interfere with the egress window fully opening. The distance from the egress window to the back of the Egress well must be at least 36" The minimum area of the egress well must be 9 square feet. (width x projection) Egress Ladders and/or Steps Egress ladders and or steps are required on window wells deeper than 44" and must be permanently attached. An egress ladder or step may encroach into well up to 6". Steps and/or distance between rungs of the ladder can't exceed 18". The rungs of an egress ladder must be 12" wide or greater and must project a minimum of 3" away from the back wall, but can't exceed 6" from the back of the wall.