I find them interesting but have not kept them cause as this article puts it:
Vampire crabs are not freshwater crabs, they are semi-terrestrial animals. They are sociable, omnivorous, pretty hardy and easy to care for.
aquariumbreeder.com
"their ecology and biology is still poorly studied." In other words, do they really only get only "up to 2 years old" or do they just die young cause good care isn't provided, like with vampire/bamboo shrimp?
This article says they need more land as water, but realistically how many gallons would you have for the shrimp, like one?
Cause even if you have "half land, half water" that really only means 25% of 10 gallon at the most for the water part, but probably less as you wouldn't make the land 50% height of the tank. Typically shrimp don't do well with other crustaceans like lobsters and crabs, this is worse in a small environment, so it won't be a good idea in a 10 gallon tank. Do post a pic of the terrarium if you decide to get the crab.