When you write the publishing contract, add a clause listing, in great detail, what absolutely has to be in the final product and what can be taken out without penalty in cases of force majeure, if the publisher pushes up deadlines, demands last-minute changes or refuses to give you an extra month when your entire programming team comes down with mononucleosis. But it will. Again, being extra careful with the contract's wording will limit the risk of aggravation. Conversely, if your publisher acts in good faith, it is your job to keep them happy. This way, you will build up their confidence in you, and they will be more likely to let you deal with problems your own way instead of parachuting one of their trouble-shooting experts into your studio at crunch time.
Some licenses come with enormous libraries of music, cut scenes, characters, etc.
Obscure licenses may be worth picking up on the strength of these ancillary assets alone, even though they might not generate much in the way of extra sales. For example, if you are producing an adventure game set in Chicago in the 1930's, you might be able to acquire dozens of hours of music for a few thousand dollars if you license an old gangster TV series to which composers sold all of their rights. Might be worth investigating. You would be surprised at how many managers don't bother. Even if it has been proven that productivity starts to tail off after about two weeks without any reinforcement.