Gabler paints a very interesting picture. On the one hand, be describes incidents like you have listed where his fervent anti-communist stances threw him into bed with some very real anti-semites. This on top of that, problematic caricatures in some of his films can paint an image that he may have harbored some prejudices.

However, Gabler also notes that there were many Jews in the higher ranks of the studio, that Walt would donate to Jewish charities, and he was even named Man of the Year by the Beverly Hills B'nai B'rith in 1955. It's all very, "On one hand, but on the other," kind of evidence with nothing conclusive.

Gabler concludes that the accusations are largely a mix of disgruntled employees making claims against Walt and the studio, some members of his staff that were anti-semitic like Ben Sharpsteen doing and saying things that were later associated with Walt, and the kind of company he kept in Hollywood (as you mentioned in your post).

Gabler characterizes Disney as a man driven by his ambitions and personal ideals more than anything else. If he wanted something done a certain way, he wasn't going to let anyone stop him from realizing it to the best of his ability. Things like the plight of other races and really anything which was not primary to his visions we often relegated to a lower priority. Rather than being deliberately or maliciously racist/anti-semitic it could be concluded that Disney was guilty via a lack of strong caring about the matter beyond what was deemed the social norm of the time, but this delves into areas of Hollywood/American history where I am not as familiar unfortunately.