Costa Rica - which seed?

I am in Costa Rica.  It is a few days before the shortest day of the year but we get 11.5 hours of sunlight per day.  As the months pass, this will extend to a max of 12 hours and 45 minutes.  Essentially, there is little difference throughout the year.
 
Even though we are in the northern hemisphere, we are hitting Summer about now.  That is, it is no longer the rainy season and we are entering the dry season.
 
With regular plants, they take their cue to flower from the shortening of the day.  With autoflowering this cue is not needed, but the yield is far lower.
 
If I buy regular sativa-dominant seeds now, will they still flower and produce a crop considering that the days will very slowly get longer?  Or am I restricted to the auto-flowering strains?
 
 
(I do have a useful tip for locating grow spots: Use Google Earth.  Zoom into a potential location.  At the bottom there is a date showing old images of that area.  Click it and you will see all of the snapshots through time at that location.  It can show up trails in the locality that might only visible during the Winter where there is less vegetation, give an indication of regular crops (usually planted in a line (fields are small here often with irregular outlines) and also show the vegetative cover in a spot during different months of the year.  I've used it to potential find spots, but just as importantly to exclude some too.)

 

Would a landrace (pure strain) be restricted because of the lengthening days?  I mean, should I have planted several months back or would it grow (and flower) independently of when I planted it?

 

I wrote to a seed bank who said that a regular (feminized) sativa will flower in about 4 months +/-   Does this sound about right?  I imagine that they will be monstrous after 4 months of vegetative growth...