In my opinion these two sentences have different meaning. In the sentence "When/where there's a will, there is a way", "will" means desire or a wish. So if you desire/wish/want something bad enough, you can make it happen- "there's a way". The other sentence "what's meant to be, will always find its way" is similar to "whatever will be, will be", it's talking about destiny and fate. If fate allows it, it will happen.