anniversaries

Celebrating birthdays and anniversaries

Q: Thanks for replying for not celebrating birthdays and anniversaries. But if someone invited us, then we should not join them and make an excuse right? And if we just had a dinner at home with family and give a gift to the kid and have a home made cake, is it permissible? Secondly, if someone joins the birthday party then does he come out of the fold of Islam, his wife is haraam on him and he has to renew his nikaah? Thirdly, by wearing shirts and trousers and not keeping a beard are we not emulating/copying the kuffaar? Are we not supposed to refrain from wearing kuffaar outfits?