Jij bent niet blij
Nobody is always happy. Dutch children are also not always happy.
Gelukkige Onafhankelijkheidsdag is the word for Happy Independence Day. This is translation from English to Dutch.
Happy Christmas - vrolijk kerstfeest
In Dutch happy vacations = Fijne vakantie
Zalig Paasfeest is one Dutch equivalent of 'Happy Easter'. Another is 'Gelukkig Paasfeest'. Either way, the wish is the same. And these are just two examples of the many ways to express 'Happy Easter' wishes among Dutch speakers. Most people say 'Fijne Paasdagen' in the Netherlands.
Gelukkige verjaardag
Vrolijk Halloween
I would say: 'Happy thanksgiving'. Because Thanksgiving is an American holiday, not a Dutch, there is no specific translation for it.
'Happy birthday' is 'fijne verjaardag' in Dutch.
"gelukkig nieuwjaar"
happy Easter is the same in flemish as it is in dutch fijne pasen
fijne verjaardag means happy birthday, gefeliciteerd means congratulations