Have you identified the butterflies commonly seen in your location and what are they? Are you in the fog belt or somewhat inland where there is more sunshine?

The ceanothus and rhamnus may attract the Pale Swallowtail, if it occurs near SF.

Most plants like these grow one or two feet a year, willow usually grows pretty fast.

You might want to check the expected lifespan of the ceanothus, some are not long-lived.

Ok, so--

1) I'm somewhat inland- we get more sun that SF-- temps regularly reach the 80's and 90's in the summer, very rarely over 100, common morning fog burning off well before noon.

2) Common butterflies in the area-- Western Tiger Swallowtail, Pipevine Swallowtail, Anise Swallowtail, West Coast Lady, Painted Lady, Monarch, skippers, perhaps the Mourning Cloak as well. All that's from other butterfly gardeners though, as I'm pretty new to this. Perhaps if Joe posts on here, he can give a more detailed answer about what we have around here.

I'd love to hear if people have had personal experience with the bushes-- how they grew, how fast, how high, lots of butterflies? etc etc

I figure you guys have got to be the real experts on that.

Most of the real experts on this forum are in the midwest and back east; only 3 or so regular members are west coast.
So to know how big and fast your plants will be near SF, the label on the nursery stock may be your best guide.

The tiger swallowtail and mourning cloak use certain willows, and perhaps you can get a pipevine to grow up one of your hedge trees, but the rest of your common butterflies use herbs or smaller shrubs as hostplants. The california sister butterfly uses evergreen oaks.

The blossoms of the ceanothus and wax myrtle could attract butterflies, you would have to keep an eye out for nearby plantings in bloom to see if that is the case.

It sounds like you have enough sun to make the effort worthwhile.