Those are lovely Scheffleras.
Typically I water thoroughly once a week my Scheffleras. If it gets into the warm to hot temps period, then I may have to do it twice a week. That would be when temps start to go into the 90F(32C ) range and higher.
I looked at your prevailing temps, looks comfortably warm at daytime and overnights are not bad. They are outdoors, so it will have good dry out time and ventilation. So if it were mine, I would improve watering. At least once a week thoroughly till you see water exit the drain holes, make sure to empty those drip trays. Nice to know your location is coastal, that really helps cool down your plants as well as the shade from your garden.