Sad to say that you are not even close to having all the needed data. First, unless real estate is a premium, I'd never put panels on a roof because you will likely need an engineer to sign off the roof loading. Do you have the isolation hours for the particular site? How is your southerly view?
As for the turbine, how's the wind conditions at the proposed site? If the turbine is close to the house, how is it's noise level rating? Is the neighbors to the north of the properly going to get "shadowed" by the "flickering" turbine? Will be high enough to get favorable winds? Does local ordinances have a height restriction? Is the turbine a suitable match for the wind conditions?
As for the equipment, who will be maintaining it? What is their aptitude as for taking care of it? What is the actual estimated electrical load as it each load and it's anticipated length of use, per day? How much is the customer willing to spend now? How much is the customer willing to spend later? Is the system bring connected to a utility? What does the local ordanaces have to say? Will there be a backup generator that will automatically or manually start when needed?
You may want to find a local advisor like a reputable supplier. Maybe take some courses and read read read on the subject. There's plant of good and not so good equipment out there. Too big or too small of a system will cost your customer needlessly. For get the customer being a minimalist. One light will lead to two lights. Two lights will lead to a coffee maker. The coffee maker will lead to a microwave. It will happen. I have dealt with many off gridders...
