1.) The 7S' of McKinsey covers a much larger scope. Moreover it is designed to asses and carefully follow changes that take place internally. Hence, this strategic model is designed to deal with internal issues. As I continued reading the post, I noticed that some elements have been changed from the original model but in essence still focuses on solving internal issues. – Organizational/Team Management Strategy.
2.) On the other hand, a situational analysis is focused more in devising a plan to solve external issues. Notice that most questions and research that you need would follow on how your brand and your competition is doing in the market, your market's (human) activity and perception, and natural, economical, and political issues that might affect your business. – Executive Marketing Strategy

Based on these assessments, I have come to a conclusion that the two strategies are very different. The 1st strategy is a management model and the 2nd strategy is a marketing tool. Thus, I'd have to say YES. I think these two strategies can be used together in any business. Apply 7S' in managing meetings, brainstorms, or any organizational issues and activities while utilizing the full potential of making a situational analysis when dealing with external issues and for marketing.

I hope I was able to give you a satisfactory answer. Please feel free to ask me for clarifications if there should be any. Thanks for that wonderful question Nick.