Stocking, water parameters and tank mate questions!!!?

I have 4 tanks. One is a 55gal with 3 parrot fish, 6 yoyo loaches, 6 glow tetras and a bristlenose pleco.

The 39gal hex has 3 angelfish, 5 Cory cats and a Bolivian ram.

Then I have a 10gal that I breed pink and blue ramshorn snails and shrimp in.

The last tank is a 30gal long. German rams are my favorite fish and I'm going to use that tank to try to breed them. The tank has been established for about a year and a half, and has alot of live plants and driftwood. I should be getting the 8 I ordered within the next couple days. The only thing in the tank right now is a bristlenose pleco and a mystery snail.

Does anyone have any advice on how to breed them? Also any tips for keeping their tank requirements how they are needed, I had 4 before and none lasted more than 2 months. I bought a new thermometer to keep the temp at 84 degrees and have been using spring water for the last 6 water changes to decrease the hardness of my water.

I know that 8 is alot for a 30gal so after they mature and pair up is there any other tanks they could be in without getting killed and stressed?

And last question, should I have a small school of dither fish with them to keep them more comfortable? I was thinking about neon tetras or guppies.

Thanks!