mama
In Chinese, you can say "妈妈,你好" (māmā, nǐ hǎo) to greet your mom.
wo ai ni mama
I assume you mean "in Chinese" and I'm going to assume when you say "Chinese" you mean mandarin. "Wo Hui Lai Le" means I've come back or I'm back. Remember that Chinese is not a language, just like American and Canadian are not languages.
The Chinese symbol for mom is "媽媽" in traditional Chinese and "妈妈" in simplified Chinese.
yes she is black/African-American and Chinese
You can say "回来了" (huí lái le) in Chinese to mean "I'm back" or "I have returned".
Say that your mom needs it for something
妈妈 [mā ma] The first 'ma' is a little higher in pitch than the second, and both rhyme with 'car' in English.
In Mandarin Chinese, the equivalent of 'whatever' is 无所谓 (wú suǒ wèi).
A leopard.
You can say "我会回来" to mean "I'll be back" in Chinese.