I know that in the Caribbean we have to make sure that we use an US/EU card set up so that as the yachts travel from area to area they can keep cell service.
I pulled these frequencies from gsmarea.com:
GSM 850, GSM 1800, GSM 1900
UMTS 850, UMTS 1900
LTE 700(28), LTE 1700(4), LTE 2100 (4)
GSM 850, GSM 1900
UMTS 850, UMTS 1900, UMTS 1700, UMTS 2100
LTE 700, LTE 800, LTE 1700, LTE 1900, LTE 2100, LTE WCS 2300 (30), LTE 2500
the 3g and 4g are the same frequencies that I deal with in US/ Carib/ and Eu so I would venture a guess that an US/ EU router will work in south America no problem.
as to the speed “bonding” when we try to use them simultaneously. the weaker service tends to drag the others down. (maybe the way I have been setting them up but for us that is the reality)
hope this helps