What do the numbers on transistors mean?
A voltage doesn't pass through anything. But semantic details aside, yes, I suspect these numbers are the absolute maximum ratings for your transistor. You do not want to design with those alone.

Yes, at least approximately. The gain is usually used for small signals, so getting to the max. might require a (very) slightly different base current. Do read the fine print; the maximum continuous current likely requires keeping the ambient temperature below some value.