Steve, there is no problems with maiden and married names. The issue is only passport validity
The safest route is renew passport. Period
Emma has no problems exiting or entering UK or Philippines.
Only place to find out about is HK.
But........
Personally, I would not want to have ANY issues, even if I was legally correct the immigration officials do have extraordinary powers all the wolrd over. I've been there mate.
Get a new passport.