This sounds like quite a late planting time for broadleaf evergreens, which risks winter damage since roots have less time to establish before soil surface water freezes and becomes inaccessible. (Evergreen leaves keep gradually losing water during winter, which the roots must be able to replenish during thaws.) The hollies are also quite large, which means they may take much longer to establish versus younger specimens; perhaps two to three years instead of only one.

This appears to be abiotic damage, meaning not caused by pests or disease. Environmental stresses, such as root dieback from overly wet or dry soil, delayed root regrowth from losses or injuries during transplanting, and perhaps being planted too deep overall, which can deprive roots of optimum levels of oxygen and gas exchange. Although the trees certainly don't look badly compromised, see if the nursery who installed them covers them under a warranty in case they decline in future months.

Leaf damage looks quite minor, and is also likely due to abiotic issues, or perhaps exploratory deer nibbling. (They don't prefer American Holly, which these appear to be, but still can taste anything before realizing they don't want to consume more.) The straight-line browned tips looks like simple breakage, where the snapped section didn't actually tear off, but just dried out. Inconsequential insect feeding may also explain some of the irregular and sporadic leaf holes. The natural shedding period for evergreen hollies is mid- to late spring, when they drop their oldest foliage and any leaves which are too damaged for the plant to bother retaining. You may see some of these half-burnt or chewed leaves dropping at that time, though there's no cause for alarm if they fall earlier, so long as there's no widespread leaf loss. American Hollies are quite adaptable to shady sites, but they may retain fewer leaves in heavy shade, especially on lower or interior branches as these areas receive the least light. You can trim off leafless twigs if they're an eyesore. Usually, hollies retain live and leafy branches all the way down to the ground unless removed via pruning, though the degree of this is also influenced by light levels.

There's no need to apply any treatments, nor would fertilizer be useful, so just give them more time to settle-in and keep monitoring them for irrigation needs. Feel the soil about five inches down to gauge moistness before deciding when to water, and soak the root area well when it's needed. They shouldn't need water if the soil feels damp when probed. In wild habitats, American Holly seems to prefer moist (but still well-drained) sites over drier sites. Continue checking into autumn, as we have experienced abnormally dry spells capable of causing plant damage in recent autumns. Evergreens can take awhile before damage manifests in overt symptoms, so drought stress, for instance, may not visibly impact growth until the following growing season.

Miri