What kind of spider is this and is it poisonous?
It's a Mygalomorph spider, of the sort which are usually called Tarantulas.  This is told by the two long, upcurved spinnerets and the large, dish-shaped carapace, with the eyes clustered in a clump - looking rather like the disk of the USS Enterprise from Star Trek, if the command bump was placed near the front edge.  I'm not sure which species it would be, but the good news is that like almost all spiders, it's pretty much harmless to humans.  These guys do have large fangs, though, so if you got bitten by one, you'd feel it.  As far as I'm aware, the venom of South American species is no big deal, so the feeling of being poked by a big needle is likely to be the worst effect.  Presumably they were entering your house to hunt for the small animals which share your home with you - large insects, small mammals and lizards, maybe.  I'd post an image, but I'm not sure which tarantula this would be (not really being a tarantula guy), and you could probably do as good a job of searching the internet as I could.  However, here is a resource I was able to turn up with a short search:

ttfnc.org/livingworld/index.php/lwj/article/download/479/462

As I said, I'm not really a tarantula guy, and so am not confident as to a specific ID of this spider.  However, having been pressed for an image, there are in this article some images of a spider which may or may not be yours.  The images are, however, tarantulas from Trinidad.  You will need to page through to the end of the article to see them:

http://sciencepress.mnhn.fr/sites/default/files/articles/pdf/z2017n2a5.pdf