] Do you really believe that JA really appreciated our so- called inequalities in her society? i.e. servants, slavery etc.

It's important when thinking about JA to distinguish between her attitude to servants and to slavery. I think you're right when you say that she accepted the notion of the servant class, but there is evidence that she had a different attitude to slavery, much of which appears in the archives here, so I'll just summarise it.

] Is there any evidence that JA ever went to an industrial town, a coal mine or factory and saw the *real* inequalities there?

Probably not.

] Did she ever go to a plantation and see slavery first hand?

No, but she certainly knew someone who had: one of George Austen's students was from plantation-owning family in Antigua.

} Did she ever meet anyone who could have given her some anti-slavery information?

Almost certainly. Britain at her time was awash with anti-slavery information, since there was a massive campaign against it, particularly against the slave-trade. And she wrote that Thomas Clarkson, one of the leading Abolitionists, was one of her heroes. By the time she wrote Mansfield Park, the anti-slave trade sentiment in Britain was so strong that the British negotiators at the Congress of Vienna had to include the abolition of the European slave trade as one of their requirements for the Congress.