I have a standard 15 g tank also. I have 6 Neons Tetras , a dozen Red Cherry Shrimp and there was 3 Celestial Pearl Danios but two died after nearly three months for no apparent reason.
There wasn't anything wrong with the water going by the test kit I use(API), and all of the fish were eating ok. When I first bought them they were juvies. Now the fish look like body builders on steroids!
I've been debating about adding more of the same fish or getting another variety thats about the same size when full grown like the "Chili" Rasbora. Alot depends on how the Neon Tetras behave with shrimp fry. When I first bought fish to cycle the tank, having shrimp wasn't a even a consideration for tank mates.
I can't give advice on the Dwarf Cichlids as I've never had Dwarfs, but I have had Convict Cichlids.
After about 5-6 months the Convicts became very territorial and would attack any fish that got close, and they crippled a smaller fish. I finally gave them to a friend who had single species tanks for Cichlids.
So far the Neons or CPD haven't bothered the RCS but I am worried if they'll eat any shrimp fry.
If this happens they are probably going to go to another home as I would like to breed the CRS. Whether you decide to breed them or not please remember to have some places for them to hide like plants and caves for molting, having fry, or just hangin' out!
Before I got the shrimp I was looking up the water specs needed for them. From what I read online there wasn't much agreement on the maximum amount of Nitrates they can tolerate.
Supposedly,anything between 0 & 80 ppm was ok, according to some shrimp articles,some of what I read listed 50 ppm max, and the seller I got them from said 10 ppm max so thats what I went by.
If you stay right around the 10 ppm limit you should be fine. Considering that the sellers shrimp were healthy and breeding at 10 ppm of Nitrates that fine with me!
(I was advised to have leaf in the tank by the seller to give the shrimp a snack.)
About 1/3rd of the female CRS appear to be near pregnancy so I guess we will see what happens (with the neons).
My water is between 5 & 10 ppm (Nitrates) and 0 ppm for Ammonia & Nitrites. pH is 7.4 and hardness GH/KH is 89.4. Temperature is 79 "F".
PS: #1) Even if the Dwarf Cichlids can't eat the shrimp they might stress them out with being attacked.
#2) When you first get the shrimp they won't look red. It takes a few hours to change colors. They look great on dark substrate. I'm using black Eco-complete.
#3) As the CPD's grew their coloration "filled out" .