I got two staghorn acro frags today!

While I was acclimating them one got touched by a lobo and that area is dying. :(
It's on top and could be easily removed.
What will stress it less: breaking that injured area off or leaving it on?

Also I ordered two BROWN acros to fit with my Caribbean tank.
I got one beautiful, perfect brown one and one green with purple one.
Assuming that I can keep them alive in the first place will it be possible to turn the green/purple one brown (heavy feeding, etc.) or are some just resistant to changing into brown?

A green/purple wouldn't fit in very well.