Speak to friend (1) about the issues in the cons list as he appears to have good friendship qualities and if your concerns are aired, could strengthen your friendship in the long run. Friends need to feel comfortable being honest with one another. Friend (2) hasnt been around much but may still have friendship to offer, again speak to this friend and air your opinion.
Yes, volunteer work may open up a new social circle for you. I have found that friends can come and go for whatever reason, the 2 or 3 guys I regard as my best friends, I didnt even know them 6 or 7 years ago and I never speak to school friends or childhood friends as we all moved on in different directions.