You can grow most types of plums in NJ but you may want to plant 2 trees of different varieties to insure consistent cropping. Of the many varieties of J. plums I've grown here in z 6 NY state I think Satsuma is probably the best for the home orchard. However you shouldn't believe that deer are all to keep you from getting fruit and most casual growers fail to get anything from their fruit trees in the east. If insects don't destroy the fruit the squirrels or other animal thieves often take them before you get them. All of these problems can be overcome but it requires a certain level of commitment.

Have you already planted the Berberis hedge? If not you might want to reconsider planting an entire hedge of this. I grew up with a Berberis thunbergii hedge in z6 OH, and IEM due to the thorns it was uncomfortable to prune, caught every leaf and piece of blown trash in the neighborhood (so needed frequent cleaning), and made walking barefoot in the yard impossible since it shed thorny twigs. It was homely in winter with a densely twiggy form decorated with whatever had blown into it in the last few days (lots of oak leaves!) I think individual Berberis mixed with other plants for your hedge would be both more attractive and more pleasant to maintain if you choose to plant Berberis. Berberis thunbergii (the most common species found in nurseries) is considered an invasive exotic pest plant in TN, though there are native Berberis in the US. Invasive means that birds eat the berries and spread the plants into wild areas when the seeds pass through their digestive systems, though you may never see a volunteer in your yard. Here in NH I have quite a number of B. thunbergii in my woods (along with buckthorn, honeysuckle shrubs, and bittersweet), so I am always appreciative when folks choose not to plant invasives. I like Enkianthus as well, but it's a member of the Heath family, so I am not sure if it will be happy in your neutral soil. I grow it where the soil is acid, and though smaller than Mike's (at 8 years or so in a colder climate), mine looks quite similar. I like the somewhat layered look to the plant in winter, but I don't know that it would contrast much with the barberry. In addition to colored twig dogwoods, you might consider some of the dwarf forms of fruit trees, such as weeping crabs or cherries. I am not sure if there are any that will stay as narrow as 5', and you might want to check for disease resistance as part of your search. I have seen some Japanese maples with narrow form, but I don't know specific varieties, nor how tall they ultimately will get.

Does your road ever get plowed to clear snow in winter? Ever get salted? If the answer to either question is yes, you don't want shrubs, especially evergreens like boxwood between the road and the fence. Also, how much room is there? I am not entirely sure that there is room for boxwoods in that spot unless you want to learn how to shear them when they start to get larger a few years down the road. Do folks ever park along the road? If yes, how would a passenger get out of the car? While what you have there may have gotten weedy and out of control, there may be other perennials that will do well there if you plant just a couple of types of hardy, dense-growing perennials such as one of the groundcover perennial geraniums. Regardless of what you have there, it will need something for weed control, but which plants you choose may increase or reduce the amount of weeding. The easiest is grass since all you have to do is mow and weed whack along the fence. Dense growing perennials of just one or two kinds might work. If no snow, some densely growing shrubs might work if well-mulched. Regardless, anything other than grass will need some weeding, at least for a while until it fills in, and even then will need some a few times annually based on my experience. For your backyard, are you interested in tall deciduous trees or evergreens, or do you want shrubs? Or some tall and some shorter plants? Is it more that you don't want to see all of the neighbors' yard or just all of the fence? Do you want year round coverage or is that not important?

A hard cap at 35' would probably be dependent on pruning ... trees don't read their descriptions or just magically stop growing at some maximum height. I wouldn't recommend doing lines of monoculture ... if disease comes through, you'll lose them all, whereas if you have a mix of different species, you're less likely to lose all the tdees at the same time. Something like a yew would take well to pruning to whatever height you want ... ideally you'd want female bushes to avoid the pollen the males spew. An eastern red cedar (Juniperus virginiana) is a native conifer for the eastern US. It's a little prickly but won't drop a bunch of cones or anything to clean up, though it will eventually want to exceed your 35' cap. Something like a mid-sized spruce might be about the height you're looking for, though it would have cones. You could also look at some of the rhododendron varieties ... they can get pretty big if you pick the right one.