7D is a good choice for "photos of animals (which are often running and jumping around) ", definitely beats 5D2 for AF speed by all reports.
5D3 is probably worth 3x 7D, the question is, do you have 3x $$$? and do you want to use it in a 5D3? I'd say no. Use the 7D for 1-2yrs and switch to 5D3 if you still feel you want it.