Lily,
My friends also are supportive, i like to tell people i know well in person if they live close enough, i will call and see if they are going to be free as i have something important to tell them, i go over to their homes, people are much more at ease in their own homes, one couple was relieved as they thought i was going to tell them i was dying, another couple told me they thought i was coming over to try to get them to buy a timeshare, in both these cases they thanked me for doing it in person.
One couple who i was their best man at their wedding in the 70's, i wrote them a letter and put it in their Christmas card, i got a christmas card back addressed to Paula and a letter inside, they say last time they saw me i seemed different, their tone was of someone grieving a death, but that is to be expected, and they say they accept.
My really good friend who was the first friend i told and is bi, she initially took the news well, however a couple weeks later was standoffish with me, then a few week later back to being good friends again, over the last 5 months she was standoffish again, i believe because of the dramatic changes she sees, but lately she is back to being good friends.
If they are as good of friends as you say they may take it ok and might be your biggest supporters.
Paula