While Miss KT did not go on to grad school, she went to college 800 miles away from me, totally on her own, and she had to grow up really quickly. I'd like to answer, hope that's all right.
1. First off, while they are your children, once they're in grad school, they aren't children any longer. Be accepting of the new ideas they are trying out as they find themselves during the process. Some of those ideas and situations will be better than others. Some of those ideas will need to be challenged. This does not mean you have to be accepting of anything that is damaging or dangerous to them.
2. I don't know that full financial support is always a good thing. I think that working, at least part time, is a good way to learn that work/life balance that we all need to find. Emotional support, yes, and physical support, like feeding them occasionally and letting them do laundry at your house if they're local, yes, unless of course they are total DCs. Then you decide what contact you are willing to have.
3. The main thing I noticed when Miss KT graduated from college was her inner strength. She had been teetering on the edge of professional victimhood (like her father...ARRGH!) and when she was so far away from home, she had to take care of business. There was no one else to do it. For the most part, she learned to take her lumps, have the courage of her convictions, and stand up/advocate for herself when necessary. She graduated in 2013, and is still 800 miles away, married and divorced, working full time, with good friends in her support system. She loves the city she lives in and plans to stay.