I think this might be someone mixing up names? As mentioned, Simba is past/behind PPH and it isn't located in a place where it would have a new entrance. Simba also is not a garage- its just a surface parking lot.
Perhaps the post was actually referring to the new Pixar Pals parking structure (which is adjacent to Mickey and Friends) and new security and tram loading area there but used the wrong name? The tram area opened about a week ago and the parking structure opened yesterday, I believe. But as far as driving there, I don't think there's a new entrance for parking for Pixar Pals, it just increases the capacity of the Mickey and Friends area and you go in the same entrance. It's just a matter of where they direct you to park.