I really like the idea of an affordable bayonet fork-type bike with a focus on low frontal area in development. But, I think it's essential to step back and not jump on the fit more important than design wagon.
If the goal is to grow into a brand that has products raced at the highest level or even is common among top amateurs, +25mm in stack and a shorter reach is a bad idea as a rule for a race bike, particularly if you are also playing with reach and front-end geometry. An aero endurance bike is an oxymoron, and there are plenty of aero-looking endurance bikes that customers can buy whose main function is to look the part.
If there are the resources for it, I would probably spend a lot of time thinking about the cockpit design and how to make the bike more adjustable than today's bikes, using the differences that an S5-like bayonet front end allows. The spacer system is different; the max and min spacer height might also be different. You might also gain the ability to add stack and reach in two places, both between the stem and the bike and between the bar and the stem.
Adjustable stack like Cervelo S5 combined with reach adjustment like the Simplon Pride II would be great for adjustability cockpitwise. Maybe three seatposts (?) (normal 25 mm and zero offset, and an additional forward offset to mimic a steep seat angle?)