You've thought through a lot of good benefits to doing this. Make sure you look into your state's laws regarding managing someone else's rental. A lot of the time you need an active broker license. Sometimes close friends and family are an exception to this rule though. Here are my thoughts on each of your points.
1) Great reason, it's always good to help a friend even if it's never paid back
2) This isn't always valid, but I can't speak for your friendship obviously, I just know that it always gets difficult when money and stress are involved.
3) Great property management experience for self-managing your own properties which I think everyone is capable of doing.
4) Great reason, although it doesn't always happen. I've closed one deal in the last two years from a tenant and I have 11 doors.
5) Similar to #1
One more thing to consider is the liability if something were to happen to a tenant or the property while you're managing it. Make sure it's legal or else insurance has an easy out and your friend/you could be stuck with a big problem. Hope some of this helped, and good luck!