I have U.S. and Italian passports, and will be traveling to Brazil and Argentina for the first time next year (Jan 24-Feb 1). Brazil requires U.S. citizens to obtain a visa ($160). Argentina requires no visa for U.S. citizens, but charges them a reciprocity fee (also $160).
Italian citizens don't require a visa to enter Brazil, and they pay nothing to enter Argentina.

Since I hold Italian citizenship, could I avoid getting a Brazilian visa, and paying the reciprocity fee in Argentina?

But, here's the problem: My U.S. passport name is 'Joseph', while my Italian passport name is 'Giuseppe' (Italian for 'Joseph'). Both passports have the same surname.
Airlines require that the ticket name and the passport name match. Therefore, I cannot use my Italian passport because the names don't match, which forces me to use my American passport, which would require me to obtain a costly visa.

Is there any way around this? I hate the idea of paying over $300 in entry fees because of a minor technicality, especially when I am eligible to pay nothing.
Could I possibly use BOTH passports?

My itinerary:

EWR-IAD
IAD-GRU
GRU-SDU
SDU-GRU
GRU-EZE
EZE-SCL
SCL-MIA
MIA-JFK

I appreciate any input.