Is wildebeest Kosher

Gazelle are specifically named in Deuteronomy 12: "... eat as much of the meat as you want, as if it were gazelle or deer ..."

However, while some animals are forbidden, the fact that an animal is not forbidden does not automatically make its meat kosher, it just means that it can be kosher. The animal must still be slaughtered properly, butchered properly, and none of "the thigh" (generally defined as "the sciatic nerve and its branches", which in practice works out to "just to be safe, don't eat the back half of the animal") is kosher. Meat "offered to idols" is also not kosher, and "all fat is The Lord's" (so don't eat it).