I wouldn't mix Bolivians with blue rams because they have different water preferences. Bolivians are, overall, a hardier fish and are probably ok holding their own with some kribs (although that really IS a lot of cichlids in a 45, particularly if any start spawning). Both Bolivians and kribs like cooler temps (low 70's) and have a more forgiving range of acceptable water parameters. Microgeophagus ramerezi like it warmer and prefer lower pH/softer water. It's my experience that they're also more sensitive and less hardy than Bolivian rams. There's a good chance they'd get outcompeted for food in your tank.