You should think about it in terms of individual council decisions: if you are voting on an issue that may be influenced by contracting work you are doing (or the vote will influence your work), then you need to declare the conflict. If the conflict is serious, you should recuse yourself from the vote.
Since NF is our financial sponsor, its hard for me to think of a potential conflict with receiving money from them. Perhaps if the NF contract was related to a different project?