Usually, the longevity depends on few factors including the application environment (how many sunny days, how often the battery get fully charged etc), but in general, we recommend reassessing the battery if solar powered lights are in about 1.5-2 years. If there is a decline in performance, in some cases the battery can be replaced. These particular lights come with 12 months warranty, so if there is any issue within few months, the product will be replaced under warranty.
As to the connected lights, there are no solar stud lights with this grade of protection from the impact that is linked to one solar panel, but we have similar solar ground deck lights that you may have a look at: https://sunnybunny.com.au/solar-lights/solar-path-lights/stainless-steel-in-ground-buried-solar-deck-lights-outdoor-kit.html#/74-emitting_colour-white/139-model-6pcs