Rams can be difficult given that most german blue rams on the market are from poor breeding standards.
In some cases they just can't handle the water conditions of certain places.
For example, i can't house rams myself unless i use RO
water. My pH is too high as is my general and carbonate hardness in the water. That and Rams around my area aren't from particularily great breeders.
As for keeping them in your 30 gallon i would go with 6. Have lots of caves setup and a fair number of plants (most broad leaf ones). Be sure that you have 2 males and 4 females. If your LFS
can't distinguish between them then go somewhere else. If you have equal or more males they will not only fight one another but they will also stress out your females to potential death.
As for peat, that will do 2 things. First of all it will tint your water to a brownish coloration. The other thing it will do is lower your pH. Driftwood will also lower pH but you need a lot of driftwood to have any effect. The tannins in the driftwood is what give it this property.
As for central american cichlids being less agressive, that is a double edged sword. While African cichlids do tend to be more agressive, there are still quite a few that are not as agressive. Yellow labs are one of the most doscile african cichlids out there. The same holds true for Daffodilli and kribs. The fact of the matter is, most african cichlids are VEGETARIAN where as most central and south american cichlids are meat eaters. What this means in the long run is, if you have territory battles, most african cichlids will fight but rarely to the death. It will be a huge fight with lots of battle scars, but there will be a territory understanding. The american cichlids will generally fight to the death and then eat thier opponant.
I have seen african cichlids in with doscile fish before, hell, i even have kuhli loaches in my my african cichlids and they are all still alive with nothing wrong with them. Though when i kept angelfish and rams (both types) they killed EVERYTHING in site or anything that came into thier territory. Infact my bolivian rams killed one angelfish I had that had a disc circumferance of 4.5" ... the ram was 1.75" in length. Then again, a breeding pair of angels that i had killed everything in my tank regardless if they thought they could or not.
Someone suggest shell dwellers, i really recommend those little guys. You can read up about the one shell dweller that i kept, Neolamprologus Ocellatus. Great fighters, great action for a lower part of the tank and they aer AWESOME parents
Hope that gave you a little bit of information to think about