I confess, I'm curious - why would anyone want to spend millions of $$ to revive a 40-year-old mega-flop with a clumsy rather dull book and a merely fair-to-middling score?
I saw it once, decades ago, at a community theatre, which is really the only kind of production that show can hope for. It was sweet and rather soporific.
I don't think there is a song in Angel called "How Can I Love Him?" Are you thinking of "How Can You Say Goodbye?" or "If I Ever Loved Him?" They're both rather pretty songs.
I assume you can license it, since I've seen one and heard of other regional productions (although that was a long time ago; I don't know if it's done anymore). Try Samuel French's website.