Mike, in your size tank you should have no issues establishing two species of Genicanthus. I would push you to add female(s) of both species though, as that would give both males "something to do", and create less of a territorial dispute in case the odd man out decides he wants a lady too!

You should have no issues with your existing angels either, I'm not sure how your pair is but some established multicolor pairs become quite aggressive, however normally only towards other Centropyge.

With that said get them from a very good source, ensure they are eating well and don't have any decompression issues, and QT the heck out of them. They're very commonly imported with decompression issues and flukes, flukes is easy to overcome, the other not so much. Of course, you'll want them to readily accept prepared foods so they can compete with your existing stock.