Pair of very small humming birds, male (I think) flying female nearby in trees.
No interactions present.
I think you are right with your identification. I suggest you enter a revised identification though including the Latin name Mellisuga helenae; iSpot works on scientific names so including it will open up the carousel linking to other sightings of the same species (always a good check to see if you have it right) and will allow you to get credit for the ID (otherwise someone will throw in the Latin name and they will end up with the credit).
I have added the latin name as you suggest.
I was told this is the world's smallest bird and it certainly was tiny, no more than about 4cm, which made it hard to photograph from the ground as they were around the tops of some fairly tall trees.
They certainly are small, I’ve not seen this species but have seen others on the American mainland and they are tiny. The Bee Hummingbird is close to half the size of the UK’s smallest the Goldcrest/Firecrest.
Indecently (sic oops a bit Freudian there perhaps, should have been incidentally of course) you seem to have the first observation of M helenae on iSpot which is why there are no carousel images linked.
Lat/Lng: 22.14, -80.44
In woodland near Cienfuegos Reserve