I’ve not read the article yet, but here’s a quick shot at the questions.
“1.) How does gravity get out of a black hole?”
It doesn’t. Gravity is not a force, it is a feature of the geometry of spacetime. Spacetime is influenced by the presence of the mass of the black hole; not by anything that has to escape from it.
“2.) Why is the speed of gravity restricted to the speed of light?”
Gravity does not travel. What travels is information about the presence/nature of the mass in question. Exchange of information is limited to “c”.
“3.) What is opposing the black hole so that the black hole gravity does not go to infinity (What limits the collapse)?”
If the centre of a black hole is a singularity, this is defined as a point where spacetime curvature is infinite, so gravity is infinite. Obviously, spacetime could not become more curved, and the area of infinite curvature must be infinitesimally small, so it is self limiting.
