Here's my thiughts plus a few other observations:
As to whether Mr Jones was a sympathetic character, I think he was more sympathetic than he was made out to be by Major. What looked like abuse from the animals' point of view may not be so from the practical, human view. For example, he did feed the animals and look out for their welfare (could have done better but shown by him getting up in the early hours to ensure no foxes were attacking the animals)
I think Major did misrepresent humans - by using emotive language and words like slavery, starving and telling the animals what miserable lives they were living - in spite of the fact that none of them appeared to be miserable! They only believed they were miserable when the idea that they could 'have more' was planted in their minds.(live forever on paradise earth, don't get destroyed at Armageddon...)
In a way, too, Major was probably the least likely to experience hardship, even in lean times - he was the prize boar and would have had extra special care lavished upon him (eg having his own stall). He was described as being fat - compare with the declaration that they are barely fed enough to live on!! (Lies, lies lies!!!)
I loved the way his speech started off gently and then gradually grew more alarmist and hate filled, building up from 'the miserable existence of the animals then starting to blame man and finally, man is suddenly the ultimate enemy who does absolutely nothing good to help animals! (Not sure how closely this relates to WT history, but they do appear to have become more 'hostile' to Christendom over the decades)
Finally there was the dream that Major couldn't remember which you also mentioned - strange how he 'remembered' the words to that very long song with a very simple tune!
(Pasted from other thread for clarity!)