This issue is very simple, I have personal experience. I am British, one of my kids was born here, the other in the Philippines, my wife is Filipino. Passports for the kids was very easy indeed. My wife was given indefinite leave to enter the UK.She can now apply for British citizenship having stayed in the UK continuously for 3 years( she has had the status for 5 years, but spent more than the allowed time outside the Uk during the first 2 years). But she will still need to take the citizenship test, which is not as easy as it seems, but just a matter of studying a set of facts and figures, most of which UK people have no idea about, the test really just showing the applicant is able to study in English.