Creating animations for a prototype game without any finalized models/mesh

I’m creating a game but do not have any final mesh or model for the characters, however, I want to start creating all the animations now. What is the best approach? Do I use the proxy mesh in the UE4 ART? The one that looks like a little Michelin man? Or do I use the mannequin model that is used in the UE4 templates? What are the pros and cons of each? Thank you.

Cons:
Both dont look like your final characters, neither in shape design nor proportions (I presume).
Both have no characteristics at all, so youll have a hard time visualizing your final character style animations on such generic things - unless you are one crack of an animator then you can make even the most generic shape blob look like a specific character.

Pros:
… well… you might be able to reuse animation made with these…but that was the plan anyway, so I dont really think this is a pro… on any of those.

I dont think it really matters which one you use, your animations wont be final anyway so go with whatever you can start animating quicker.

It should be relatively simple providing they are both bipeds and have similar bone names for the key joints.
You can just use animation retargeting to tranfer them to the final skeleton.

Okay so no matter which route i take, the animations can be (if i choose to) re-used in the final products?

Thanks for the help guys.

Yes, they can. You can reskin any mesh that’s suitable for that skeleton, and use it’s animations. I would usually use Mannequin, just because it looks better for me.