Beef gelatine is certainly kosher, if it is made from kosher cows, i.e. ones that were slaughtered properly and whose internal organs showed no sign of disease or injury. The only brand of gelatine that is made from kosher cows is Kolatin™.
Regarding other beef gelatine, made from cows that were not kosher, there is a dispute among the halachic authorities. Some authorities held that gelatine made from the bones of such cows is not kosher, but there were many authorities who held that it is, because the it's changed so radically that it's no longer the same substance. The rabbinic consensus in the USA is in accord with the stricter opinion, to regard such gelatine as not kosher; but the consensus in Israel and Europe is that the lenient opinion may be relied on, though it is better not to do so, and so the rabbinates in those countries certify two levels of kashrut: the basic level allows all beef gelatine, but the "mehadrin" level allows only Kolatin™ brand.
if it says halal gelatine then it is, or if it is not from beef it is halal, e.g. beef gelatine (haram) , gelatine (half-half) and last but not least halal beef/non-beef gelatine (halal)
Neither beef nor gelatine is vegetarian.
I buy Davis Gelatine where there there is written "This Gelatine is purely extracted from Halal slaughtered beef." Therefore, it's HALAL.
BEEF (bovine)
No, there is no difference in tenderness between kosher and non-kosher beef. The animals are raised in the exact same way with the only difference being the way in which they are slaughtered and that as part of the kashering process, kosher beef is salted to draw out excess blood.
NO. Kosher beef has to be killed a certain way and blessed by a rabbi. It is significantly more expensive than normal beef
This is impossible to answer, but the salt content in all kosher meat is significant.
Hindus do not eat beef no matter if it is Kosher or non-kosher.
Beef jerky is made from a part of the cow that i am unfamiliar with but definitely not pork
Your best bet would be to call a kosher butcher in the Chicago area to find out who deals with kosher organic corned beef if there's such a thing available.
Because those gum are made from beef gelatine.
Any good supermarket. Tesco sell them. Gelatine leaves can easily be substituted weight-for-weight with gelatine powder, which is sometimes easier to find.