I dislike
Emmerich, it sounds very harsh to me. I agree with the person who said
Emeric would be better, but it's still nms. For nn's, you could try
Rich,
Rick \
Ricky, or
Erich \
Eric?
Emmett is very handsome, I think it's definitely an improvement from
Emmerich. I can't think of any nn's other than
Em \
Emmy. This could be a stretch, but maybe Mitt or
Matt?
Emery, I absolutely adore. It has a soft, gentle sound - but I don't feel it's feminine. It's all boy to me, and very cute! You could always use it as a nn for
Emmerich if you want since you like both?