Neural interfaces are often given to individuals who would be working with electronic components often. Such as starship crews, armor pilots, and scientists. But they can also be given to aid in communications between groups, such as communications between body guards.
The "ninjitsu" term is used in a generic sense. In other words its the arts of silent assasinations, use of various tools in combat, use of poions, etc etc. Much like the historical ninjas of japan. The skills were also taught by royaly funded instructors, coming from various backgrounds. Additonaly, a good thief should be able to conceal themselves, thus it would be logical to have some training in concealing one's presance under the rogue skill.
The history is meant to be a tad long to make up for the dead parents issue. Also the loss of her parents at a young age is esential to the character's... um.. character (lack of a better word at the moment).