Your loads were determined by decisions you made weeks ago.
I think the biggest decision was the deep, double-loaded floor plan. The north units are about 42 feet deep from the corridor to the windows, and the corridor is only 8 feet wide. In a typical unit, internal gains account for about 83% of the cooling peak, and the narrow corridor left very little space for ductwork. If I could go back to Week 3, I would make the units shallower, closer to 30 feet, and widen the corridor or increase the floor-to-floor height slightly. I did not realize how much the band beams would affect the duct layout. On a real project, the mechanical engineer should have raised this during early schematic design, with the structural engineer involved, since beam depths and duct clearances need to be coordinated before the floor plan is finalized.
Occupant comfort is not the same as air temperature.
The Bay Area has a mild climate.
For Level 5, I think the units could manage without mechanical cooling for much of the year with operable windows and fans, since the outdoor temperature at the cooling peak is only 86°F. I would be more concerned about the Level 1 retail, which has a cooling load of about 92,000 Btu/h and needs 2,035 CFM of outdoor air, and the amenity spaces on Levels 3 and 4, which can have many occupants at once. To reduce cooling in the units, I would consider operable windows, exterior shading, ceiling fans, and using the concrete slabs as thermal mass. However, occupants would have to accept some hot afternoons, noise from Oxford Street, and closed windows during wildfire smoke events. Since the units only have windows on one side, natural ventilation would also be limited. I think eliminating cooling completely would require changes to the floor plan.
You computed loads for one typical floor.
You were told not to agonize over duct connections.
I think the important details at this stage are the ones that affect the layout or structure, such as main duct sizes, duct routes, shaft dimensions, clearance below the band beams, and penthouse location. Tap fittings, flex connections, and grille models can be worked out later as long as enough space is reserved. The problem is knowing when a minor-looking detail actually affects the design. My flex duct runs are a good example. Some are 20 to 23 feet long, and at first I treated them as a connection detail, but replacing them with rigid ducts would require more ceiling space inside the units. If fixing something later means changing the structure, lowering a ceiling, or resizing a shaft, it probably should have been addressed earlier.