Coronado has great public schools at all levels. It is a small relatively “self-contained” very walkable small town and the OP could live near their biz partner without ever having to set wheels on a freeway. The whole town (incl the strand) is safe for kids to walk and ride bikes in. There ARE lots there the size the OP is used to but those (rare) properties would likely be far above their price range. However, I think they could find something suitable there for a family of six for $1-$1.5M, although it may not have the square footage they are used to. In any case, why not RENT there near your partner while you look around the county at the different areas, try various “commutes” out during rush hours and accept longtime local knowledgeable counsel?
School is on a “traditional schedule” in the CUSD and begins August 23.