Ask Mr. Smarty Plants

Actually, that's not in our field, as we are gardeners, not entomologists. And, many of the plants you list are non-native to North America and/or to your area. The Lady Bird Johnson Wildflower Center is dedicated to the care, preservation and propagation of plants native to North America and to the area in which they are being grown.

However, we do sympathize with your problem with the Japanese beetle. About all we can do (since you seem to have tried most of the solutions we might offer), is try to find you a source that hopefully will  have better information than we do. In connection with localized gardening and especially pests and diseases, we always recommend you start with your nearest university extension program. In this case, the Rutgers University New Jersey Agricultural Experiment Station, when we searched on that subject, brought up websites both in Ocean County and in Monmouth County. Both sites have websites with contact information and lawn and garden sections, even access to Master Gardeners. We think it's safe to say that if you have Japanese beetles, so do a lot of the people living in your area. 

In fact, we found a University of Kentucky Entomology site Japanese Beetles in the Urban Landscape that said "The Japanese beetle is probably the most devastating pest of urban landscape plants in the Eastern United States." That also helps to explain why we don't know anything about them; we do have pests in Texas, but at least not that. Anyway, we learned that both the larvae (grubs) in the soil over-wintering and the beetles that emerge when the weather begins to warm are threats to your plants. Please read the entire article, as it has a lot of information on the beetle life cycle and controls. We at the Lady Bird Johnson Wildflower Center recommend neither for nor against the use of pesticides, and urge you to seek trained professional advice if you feel you must go the pesticide route to protect your garden.