Might as well respond. I have 3 so I'm going with the average of the system, which is "Other"
Annabell is, well, that's pretty normal. I just wanted a 3-syllable names that started with A.
Omega is a bit more unique. I didn't actually know Omega was a greek letter at the time I made him. The reason for his name is that often the secret bosses in Final Fantasy named "Omega" (Final Fantasy V, VII, X, off the top of my head).
Tula is the name of a weapons manufacturer in Russia, I do believe. I'm not sure though because Ivy from the Brimstone system named her.