Without pertinent data related to existing conditions, as well as some historical maintenance information, , it is difficult (or impossible) to offer suggestions.
This kind of question will keep coming up. A popular alternative among many homeowner's associations (large and small) is to enlist the services of a management firm to make these kinds of decisions for you. Your group may find the savings in reduced error greater than or equal to the cost of the service.
Regardless, we strongly suggest that you pick up a copy of Painting and Wallpapering by Ortho Books. The $7 book quickly, simply and clearly address paint lingo, safety, choosing the right paint, buying, preparation, application, mildew, and much more. An evening or two reading this jewel, and you should be able to create your own list of "contract specifications". And, don't forget: When hiring a contractor, plan, ask questions and get your answers in writing before you sign.