Hi
Considering the paradisefish you have can grow to just over 3", it's best not to add any more gouramies to the tank. A small schooling fish is probably a better choice. Maybe something like spotted rasboras or neon tetras.
As for the species you are interested in, if you ever get a larger tank, croaking gouramies would make a fine choice. They would do well as a trio - 1 male, 2 females - in a heavily planted 20 gallon along with the 4 paradisefish. Croakers get to just over 2" and are quite epaceful though the males can be a little aggressive towards each other.
Licorice gouramies stay small but are fragile. They are best kept alone or as pairs or trios in a heavily planted tank. The water quality must be excellent and their tankmates should not be anything too boisterous that will stress them. They are very closely related to the species of paradisefish you have. This could possibly make them more aggressive towards them and cause problems but, because of the size difference, it shouldn't be a serious issue. Still, you should keep them in a larger tank as they'd be over-crowded in the current set-up. They also generaly do best in a species tank with peaceful schooling tankmates or bottom-dwellers for company instead of other gouramies.
The sparkling gouramies are the best choice for a small tank as they only get to about an inch. However, because you already have 4 gouramies in just a 14 gallon, you are best off skipping these as well. They are more peaceful than either the croakers or the licorice gouramies and do well as a trio in a small heavily planted tank. If you decide to upgrade your tank at some point, maybe you'd like to put sparklers in the 14 gallon and move the paradisefish into a larger tank where you could combine them with croakers or whatever.
I should say that not adding any more gouramies is just my opinion. If you realy, realy want to, adding a trio of sparklers to your current tank should actualy be ok. Also, I'm assuming you only have the 4 fish you mentioned. If you have anything else, you don't have room for any more fish regardless of species.