1. niche
2. nee
3. albeit
4. grande prix
5. joie de vivre
As a Canadian, I use the French pronunciation for 1, 4 and 5, but 2 sounds odd spoken either way, and 3 never sounds quite right either.
1)either as nitch or neesh, depending on my mood
2)nay (French for born)
3)all BEE it
4)grand pree
5)ZHWA (or SHWA) duh veev