1. Some people are happy despite living in houses with out Vaasthu compliance. Does it mean Vaastu is simpley a misnomer ?+

No. There may not be any visible effect if the native is going through favourable planetary movement. It may come alive once the position changes.

2. What is the difference between Vaasthu and Feng-shui ?+

Feng-shui is also as old as Vaasthu and based on the same five elements with some variation.