Ferriej,
Some fast balls here ,though you do display a very sound insight into the main issues involved for a self confessed less experienced investor.
Given your posting, and objectives ,hat in the ring ,i believe that Banana Residential in Fortaleza is the better option.
Brazil is an embryonic market and as such, is primarily a capital appreciation play.Both should yield an excellent result in this regard ,so little to empirically differentiate.I am reassured you said "some" income because yields are likely to be sparse in the short term-probably even more so at Grand Natal due to length of build time.
Banana should be up,running and fully operational well in advance of the facilities even being finished at the latter.Sure there will be more facilities in the long run ,though this project may just be a tad too ambitious given the number of beds available relative to required visitor numbers.You will be competing here not only with thousands of other properties but ALSO with numerous large on site hotels.Banana has a 100 max villas and a well connected property management company should achieve a good occupancy level given the small scale of this project.Relative to its size ,on site leisure facility provision is excellent.
From a personal vacation usage perspective my inclination would be to say that again Fortaleza would probably be the better option.It is 4x the size of Natal,is more modern and quite simply there is more choice, a greater variety of activities and facilities, a better nightlife and an extended season.
Do not place undue emphasis on the airport factor.Natal will be large but a little known fact is that much of the increased capacity is geared to commercial as opposed to passenger traffic.Also bear in mind that not all visitors will necessarily eminate from Europe.The North American market is both considerably larger and closer.There are no direct flights from the States to Natal -instead they run from Miami to ..yes..Forteleza.
Incidentally, i am purchasing at both locations and in conclusion a lateral thought for your consideration-why not cover your bases by entering into a fractional ownership arrangement with like minded individuals,purchasing on a joint basis at both Banana and Gran Natal and selling the least favourite/less successful performer?This will also serve to spread your risk factor.
Hope these comments are of some use and if you have any specific queries post again or pm me.