Mexican fans knew of the boy and was already a Mexican star......he had a loyal fanbase to help that card sell on cinco de mayo. Mexican fans buy the most PPVs in this sport which is why Bob was big on owning a strong stable of Mexican talent over the years.
The attendance for the 2nd fight was higher than the 1st, but the ticket prices were lower. So, 2nd fight did worse at the gate than the 1st.
Those numbers were officially announced, there have been a few Pacquiao fights where Arum just spews what he thinks the buys will be and then never officially announces them. http://www.doghouseboxing.com/Benz/Benz-110513-PPV.htm
The first Bradley/Pac fight did 700K PPV buys. I expect this one did less, given KTFO6 and the Pac/Rios numbers.
The live gate was Pacquiao's worst in a long time so surprising if true. But there's no source and they say the #'s won't be out till next week.