I would put the Christian romance under a separate pen name from everything else you write that isn't no heat, no swearing. It's a different audience. If the NA is sexy, I would also separate that from the YA (assuming your YA is aimed at kids, rather than readers who are actually adults).
I don't find it hard to maintain multiple pen names, but what usually happens it that one pen name becomes more popular than the others, so you gradually neglect the others to focus on the one that sells best. Eventually, the least popular ones just sort of drop away, which isn't necessarily a bad thing, depending on how you feel about them.