Two lens questions for Galapagos Trip

I'll be visiting the Galapagos this summer and will be bringing two FX bodies. For the telephoto end I'm currently thinking of using my 70-200VR2 with a 1.4TC My first question is should I invest in a 1.7 TC instead? Next at the wide angle side, I'm between the 16-35 or the 24-120. I see pluses and minus to each. I'd be interested to know from those that have been if I'd need/want wider than 24 or if I'd even really need the middle focal lengths. Thanks in advance.
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Jeff