C, not sure. Modern boats seem more convenient when there is a family involved. Of course, wooden boats can be very attractive.
For what it's worth (*), RMYS have recently upgraded their club-rooms and marina and seem to be a friendly bunch of people now (in contrast to a decade or so ago) and Sandringham has probably the best facilities on entire eastern shore. I know nothing of Brighton, other than it's a blooming long walk from the club-house to the marina..
At Williamstown you have two choices: RYCV is in the best spot (and has been for well over a century), but HBYC is a friendlier, cheaper, club and the pick of the two by far. The biggest advantage of being based at Williamstown (Hobson's Bay) is that, like Geelong (Corio Bay), you can most always go for a sail of some duration in all but the most extreme weather conditions. If you sail out of the eastern shore clubs, given the prevailing westerlies, there are going to be many beautiful sailing days where you can't even leave the marina without the entire crew being sea-sick.
I'm stuck where I am for now, but if I had a choice of clubs I'd pick RMYS over the others for reasons mentioned above.
Anyways, I hope you find a place you and your family can settle into sailing and wish you well in your endeavours.
* = The above is all my opinion, of course, based on personal experience, and is probably not worth anything at all...