Tom

While it's possible Austen did pull some inspiration from family and neighbors, not all her characters or situations were; and those who assert that are just perpetuating the same tired stereotype that women can only write what they know and everything they write is their own personal experience or fantasy, which is utter nonsense. That wasn't directed at you personally PinkWeeds, but at those literary critics (like Jon Spence) who assume that and make completely wild speculations about who her characters were based on, because they had to be based on someone she knew, it couldn't possibly be any other way (for instance, I recall Spence stating that Austen's brother Henry was the inspiration for both Edmund and Henry Crawford). Anyway, had Tom been inspired from a real life person, and had that person been homosexual, it's certainly possible Austen would have realized it. Homosexuality was indeed known in Regency England, and there were even a few public figures who were openly such or were widely reported to be such; Austen even includes a homosexual reference in Mansfield Park, and she most certainly knew what it meant.
As for Tom sexuality, I don't think there's enough evidence either way. Just because he doesn't seem interested in any women in the course book doesn't really mean anything, Fanny and Mary Crawford are really the only two options we know of (although there could have been women in London or Antigua he was interested in that didn't work out that we don't hear about), and I think it proves good taste that he didn't fall for Mary like Edmund did. And Tom and Fanny are far too different. As for Yates and Julia, I think Tom's reaction was more an immature response to his friend spending more time with his family members than him, you see the same reaction in adolescents and teenagers all the time if their friend is spending more time with someone else; and Tom is nothing if not a delayed adolescent. Besides, homosexuality isn't the only explanation. Some people are asexual, in that they might not ever really find anyone of either gender attractive; other people just don't fall in love with everyone they meet and might go years without finding someone they love.

Under capitalism, man exploits man. Under communism, it's just the opposite.