Final answer:
The catalase, oxidase, and acid-fast tests are not specific for differentiating Bacillus anthracis from other Bacillus species, and while endospore staining can confirm the presence of endospores, it doesn't distinguish between species of Bacillus.
Step-by-step explanation:
A technician working with a large, spore-forming, gram-positive bacillus, suspected to be a Bacillus species, would want to ensure that the organism is not Bacillus anthracis, which is the causative agent of anthrax. The appropriate test to differentiate Bacillus anthracis from other Bacillus species is not listed among the options provided (catalase test, oxidase test, spore stain, and acid-fast stain). However, additional methods beyond those listed can be used, such as testing for the presence of a capsule, which B. anthracis has, as well as the lack of motility, and specific biochemical tests such as the gamma phage test.