Hey Pitts
The last time I spoke to the Aero Club Do Parana folks they said they could arrange for me to take my PPL tests in English so I am not sure if that was the case or not but I never took them up on the offer.
As for tax if cars are anything to go by then we are talking closer to the 100-125% import tax so your aircraft can expect the same treatment.
With regards to emmigration am not an expert but you can apply for your CPF at the Embassy in London and it takes about a week or so to get it, but for a perminant emmigration you would need perhaps a retirement visa or an investment visa and the investment visa is based on you investing a minimum of 150.000 Reals or 75.000USD and have a business plan that can provide employment for up to 10 locals and the investment visa is for 5 years afterwhich it can be converted to a perminent one.
You can get a tourist visa at the Airport in Curitiba which is 90 days and your allowed to extend it for another 90 days, or get married to a local brazilian and then after 2 years apply for your brazilian passport.
Lastly I would say forget Maranga for GA as Curitiba is way better and has a dedicated infustructure for both GA and expats, if you need anything further do not hesitate to get in touch.
Safe landings
WA