Blue rams, gold rams, and electric blue rams are all the same species -- Mikrogeophagus ramirezi. You can mix them and they will interbreed. They should be fine with other dwarfs as long as the others can take the warmer temps that rams enjoy. Rams are a short-lived cichlid, probably 2 years max, and they love water in the mid 80s. They do great at discus temps. Also remember that rams in a tank that size tend to be more middle-to-bottom dwellers, as will other dwarfs. Do you have plans for more fish besides the dwarfs? You'll need something to fill out the middle and top levels of the tank or it may feel a bit empty.
The most important thing about tank size with rams is that they all have room to create territories. They do this near the substrate which is why the tank footprint is probably more important than the number of gallons. For instance, you can keep more rams in a long, rectangular tank than in a cube or cylindrical tank. Add a bunch of driftwood, rocks, clay pots, caves, etc. along the bottom of the tank so they have areas to designate as "theirs." You will often see males defending these territories from one another.