I think they are all veiltails...
Its possible they can coexists with only 3. I had 4 together and one of them turned out to be a male. I did add in 2 more females but I also kept the male with them because as of yet - i have seen almost no fighting between any of them. Sometimes i find one with a nipped fin but nothing to serious. Keep a close eye on them though as whoever said they can be just as aggressive as male is correct. You can reduce the fighting by adding LOTS and LOTS of decor and plants. Tall ones, short ones - makes sure all levels of the tank are covered - like the bottom, middle and top.
This was how I had my 10 gallon with the 4 were still very young. If you look closely you can see all 4 of them and why I though the male was a female. Now they are in a 20 gallon long with lots of real plants