Since they are dwarfs and you'd already lost two and one was bloated before death, the problem is/was almost deffinately an internal bacterial infection. This species is particularly prone to it. Keep a very close eye on your remaining dwarf. At the first sign of trouble, it would be a good idea to isolate her into a cycled (transfer mature filter media and gravel from the main tank) hospital tank and treat with a strong broad-spectrum antibiotic. You can also dose the main tank but there are 3 very good reasons to use a hospital tank:
1) Antibiotics often play havoc with your biological filtration - messing up your main tank's water quality and stressing the rest of the fish unecessarily.
2) Even with treatment, the dwarf would be unlikely to recover. While the fish is alive, the disease is difficult to spread. Once dead, however, any fish that nibbles on the body is likely to become infected. If the fish is seperated in a hospital tank, this isn't an issue.
3) Again, the fish is unlikely to recover even if properly medicated. By keeping it in a seperate hospital tank, it becomes much easier and stress-free to euthanise the fish with clove oil if it's at the point where you know it can't recover.
I appreciate why you won't be getting more and I agree that that's for the best. Just so you are aware, however, there are some equaly beautiful and small species of gourami that would make better replacements - honeys (colisa chuna/sota) and thick-lipped gouramies (colisa labiosa) come to mind. They grow to 1.5" and 3.5" respectively. Both are peaceful and work well in peaceful community tanks kept as trios (1 male, 2 or more females).
However, considering the fact that you have angels, gouramies are actualy best avoided over-all as they compete with angels for the same territory. Small gouramies like your dwarfs and the ones mentioned above are likely to be bullied by adult angels or spawning angels. There are larger gouramies and some slightly mroe aggressive species that are better suited to an angel tank. If you are interested, let me know, I'll tell you more about those options.
Anyway, I have to point out something - you said you have 3 young angels. That's fine for the time-being (though I think you didn't mention tank size - that's realy important for both the angels and the gouramies and for seeing whether mixing the two is a good idea or asking for trouble) but when those angels grow up, if two pair off, the third is going to be bullied - possibly to death. Maybe you have other plans for the three and will be returning any extra fish anyway but I thought I'd mention this just in case
Just keep a close eye on them basicaly.