Unless you plan on building everything around the blue rams with other fish that like the water really warm, I'd skip those. German Rams and their colour varients are better suited to softer, more acidic water too. Bolivian rams are a better option for lower water temperature and are more likely to do well in harder water with higher pH.
When people are talking about water hardness with regards to fish suitability, we are talking are general hardness (GH), not carbonate hardness (KH). While it's usually to find if ones high so is the other, this isn't always the case. While both are useful to know it's for different things. KH keeps your pH stable, GH is a more a measure of the mineral content in the water, specifically calcium and magnesium.
From the fish you have mentioned, and assuming your KH and GH are similar figures, about 6 or 7 degrees (slightly hard) i would say the mollys and cichlids are the most compatible with each other and would suit your water. You could do corys, bronze and peppered corys are usually better at adapting to harder, higher pH water.
As for an algae eater, again assuming the GH is in the slightly hard range, a small pleco or nerite snails?