With a house that size, I think would also be leaning toward 400A minimum as well, before I even did the load calc. Especially when their already talking about a pool, elevator and will probably add some other unannounced future projects like a finished basement, pool house, heated two car garage, etc.
Sounds like they most likely have the resources to do things right anyway.
The best way to handle the baseboard outlets might be to just stub the wires out and let the carpenter drill a 3/4" hole in the center of the baseboard and leave them sticking out for you to cut in old work boxes after the baseboard is installed. Those Allied 9361-E, 16 Cu.In. NM old work boxes and a multi-cut tool like the Rockwell Sonicrafter with a standard end-cut blade make pretty quick, clean work of that type of thing these days.
