If Neil Finn wanted to call it Crowded House, then yes it would be. Afterall, Tim Finn, Phil Judd, Eddie Rayner, Mike Chunn, Noel Crombie and Emlyn Crowther were Split Enz, and so were Neil Finn, Eddie Rayner, Noel Crombie, Nigel Griggs and Paul Hester.
Look at King Crimson:
1969 Robert Fripp, Greg Lake, Ian McDonald, Mike Giles, Peter Sinfield
1970 Robert Fripp, Mel Collins, Greg Lake, Mike Giles, Peter GIles, Peter Sinfield
1970 Robert Fripp, Peter SInfield, Gordon Haskell, Mel Collins, Andy McCulloch
1971 Robert Fripp, Peter SInfield, Boz Burrell, Mel Collins, Ian Wallace
1972 Robert Fripp, David Cross, John Wetton, Bill Bruford, Jamie Muir
1973 Robert Fripp, David Cross, John Wetton, Bill Bruford
1974 Robert Fripp, John Wetton, Bill Bruford
1981 Robert Fripp, Adrian Belew, Bill Bruford, Tony Levin
1994 Robert Fripp, Adrian Belew, Bill Bruford, Tony Levin, Trey Gunn, Pat Masteloto
2000 Robert Fripp Adrian Belew, Pat Masteloto, Trey Gunn
The only consistant member is Robert Fripp. So if Neil wanted to call something Crowded House, he can. The question is would he?