Very Plausible with Some Plot Holes
To justify the "space-born" paradox, there may have to be an artificial origin story... perhaps the recombinant genetic engineering of two similar species of intelligent life (with artificial factors that support long-term space travel). I suggest a weak artificial gravity environment, such as rotating stations for the space-born variety. This would imply that they could potentially adapt to gravity, but would be at a disadvantage in doing so (thus creating increased evolutionary pressure for divergence into another species).
I assume that this is similar to flamingos. For mammals, there is no noted example. Either the substances in the foods survive digestion and color the blood and embedded themselves in skin cells (similar to coloring cells for microscope slides, or the way toxins in certain bugs, frogs, and rare birds can accumulate), or your creature has scale-like skin (microscales like sharks perhaps) and the pigment becomes a part of this structure like the flamingo diet which turns their feathers pink.
The food in question may need to be described in detail. Like, why isn't digging it out of the ground an option? Is this a meat or vegetable, or some sort of plant-like animal (think anemone, but land-based)? Greater strength vs. the space cousin species is likely as gravitational impact creates stronger muscle, perhaps being a reversion to suppressed genes in the engineered species scenario. The hard part is finding a proper biological analogy. Gorillas have greater strength due to the need to bend branches to eat leaves. Baboons live in the savanna, however, and seem to use their relative strength to hunt other animals or defend against predators.
The question of whether it is possible is "yes", muscles may pulse at a more frequent rate to generate greater strength capacity, or may be more dense. The real question is whether the evolutionary pressure is enough with ripping tough food being the primary reason. Perhaps adding a secondary reason (other than just the increased gravity) would help here.
UV Absorbing Skin
I assume a more pigmented thicker outer layer of skin would work for this. There are other solutions, but thicker skin would limit UV penetration to lower layers and with proper pigments the UV resistance is increased.