I never had a high BMI ever, noe on testosterone or estrogen . My BMI has always been like 17.5 or so on Testosterone. Im an ectomorph so I always had low fat and low muscle naturally and my frame is not huge (ribcage circumference is like 76.5-77 cm circumference behind just below the nipples and my wrists are also very small).
Maintaining a low BMI is a natural thing to my body, I just do intermittent fasting due to health benefits.
About beard, I just said that because it can add even more masculinity to the face but it is not even necessary if you maintain a lower end healthy BMI, because that way your bone structure will be exposed and you will not look femenine. Also I've noticed with lower BMI you have less smooth skin(cause subcutaneous fat gives smoothness to the skin) so it removes even more feminization.