Possible - but I doubt that the patent-suit split is just the same as profit just because that would highly disincetivize Momenta both in the suit and leading up to the suit (some of the patents were written well after the agreement with Sandoz was signed). Not something Sandoz would want to do when they too stand to lose from entry of a generic on the market.
I do not understand that. M & S reached an agreement to share expenses of development of mL and the rewards that flow from it. I would expect that patents to protect the venture would be contemplated even before they understood just what could be patented. And they would decide how the expenses of obtaining and enforcing those patents would be shared as well as the fruits of them.
Any agreement on the licensing of the patents that does not reflect the profit sharing terms, incents one party to act in their own interest against their partner.