She definately looks like a little fighter. I am so happy for you guys, you had such a hard time and here is the reward - sweet little Maugly. Congratulations - you are great parents
As for the sex here is an explanation I have found that helped me :
Telling a Cat's Gender
Q: How can you tell the sex of your kitten?
Answer: Both male and female kittens have two openings in the anal area. They are closer together in the female. The one closest to the tail in both sexes is the anus. In a female, the vulva is a vertical slit almost joined to the anus like an upside down exclamation mark. In a male, the tip of the penis is hidden in a small round opening about 1/2 inch below the anus. Testicles in a male kitten usually become obvious when the kitten is about 6 weeks old and clearly visible in an adult male who is not neutered.
OR
The female kitten's reproductive organs are very close to the rectum while the male's testes are between the rectum and the male organ, such that the male's organ is much further away from the rectum than the female's