They are natural, but kind of formal. Like the sort of thing you might say at a wedding speech.

Yes, they are natural, but they sound quite formal and poetic. You might hear sentences like these in a speech, a wedding, or in writing, but not often in everyday conversation. In daily English, people would usually say something simpler like: I hope you stay happy. I hope your happiness lasts. Or my personal preference I wish you a lifetime of happiness.

I hope you live a happy life.