I assume EBR is electric blue ram, so we are dealing with the species Mikrogeophagus ramirezi, which is applicable to all the colour forms and varieties of the common ram. Introducing a new ram to a tank with an existing ram may or may not work, it all depends upon the behaviourial nature of the individual fish. If the larger ram is a male, and the new ram is also a male, the new ram will likely not last long. This species is very territorial, and the existing ram if a male will consider the entire tank as his space. "Intruders" will not be tolerated. If the new ram happens to be female, the larger if male may or may not accept her. If both are female, it may work out, but it may not.
Concerning the other fish, you need to get more of the dwarf loaches. Here again there is a risk though. Loaches are very social, and they need a group of at least five, and they will establish an hierarchy within the group. Adding new loaches is much the same issue as the ram. The two you have may or may not accept "intruders," or they may and all will be well.
What are the "minnows?" If these are White Cloud Mountain Minnows, there is an issue with temperature. The rams must have warm water, in the 82-86F/28-30C. The white clouds need the temperature much lower, 60-72F/16-22C. Though not a coldwater fish, warm temperatures such as the average community aquarium (25-26C/77-79F) is likely to shorten the fish's lifespan and cause health issues. The loaches also have a problem with water temperatures suited to the ram.