There isn't going to be much you can do right now while the rain continues, except to rake up any fallen leaves/twigs.
Sorry 'bout that.
But do NOT spray vinegar on foliage, unless you're trying to kill it; vinegar is a known herbicide (killer of plants). We recommend it here as a weed killer fairly often.
The soap spray is useful against soft-bodied insects *on contact*, but if the rain washes it off immediately, I don't know that the soap will have enough time to smother the insects' spiracles. When it does stop raining, be sure to wet the tops and bottoms of the leaves where you see insects--there are usually lots of insects under the leaves! (sneaky beasts....)
The mildew (powdery mildew?) needs sunlight and air for you to combat it. We recommend a couple of sprays here, one based on baking soda and the other on milk, to combat powdery mildew. Again, you'll need to wait until the rains stop or at least let up for a time.
And...I know it may be tempting, but do not strip the leaves off of the plants. The leaves are the mechanism by which plants manufacture their own food via photosynthesis, and losing more than one-third of the leaves jeopardizes the health of the plant.
Sorry to deliver such bad news, but as soon as the rains stop, you'll be ready!
Sunset Zone 17, USDA Zone 9