Yes, you can have a person in multiple circles. Check out this post from someone else I follow
After using Google+ for almost a year internally at Google and almost a week in the “real world”, this is the best way I’ve found to manage my circles.
Step 1: Face reality
Come to grips with the fact that you will never read EVERYTHING on Google+. =)
Step 2: Make circles for SHARING
Create circles of friends that you share with (e.g. Work, Family, Church). These are the circles you use to control access to the posts you write. People can be in multiple circles. For example, a coworker might also be in your photography club.
Step 3: Make a circle for READING
Decide on a few people you really want to keep up with and add them to a separate *Inbox circle. This circle has a selection of people from Work, Family, and Church. Face it, not everyone at work or in your family is that interesting. If you can’t read everything, you might as well make sure the stuff you do read is interesting. =)
> When you share something, use your “sharing” circles. Did you take a trip with your family? Share the photos with your Family circle.
> When you’re reading your stream, click on your *Inbox circle on the left side of the stream. This will give you a more manageable amount of content than the Stream link, which for many people is already a fire hose of random stuff, most of which might not be that interesting. You may want to make a couple other circles for reading different topics. I have a separate *Inbox: Photographers circle where I read a few popular photo bloggers.
Of course, when you find yourself with some spare time and nothing to fill it with, you can flip back to the Stream tab (or even the Incoming tab!) and read to your heart's content. Most of the time though, I read my *Inbox first.
Note that my inbox circles start with * so that they sort to the top of the circles list on the left side of the stream. (Except for the default circles like “Acquaintances” - I just renamed those so they don’t automatically sort to the top).