Can anyone here guesstimate its chances of survival?
I'm an optimist, so think that it will probably survive just fine.

Where are you located?

I'm wondering if it might be best to cut it back some? If it is tall, might it need staking so the roots can take hold and root back in?

See the link below for getting your location (garden zone and location...see I am 5/6 S INdiana) set up so that it will automatically be shown whenever you make a post.

Sue

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These plants look like dead about half the time. They're native to the Baja and Mexican coastal regions but can adapt to a variety of areas. They're wired to respond to rainfall and cooler temps, basically monsoon conditions, but will often go dormant and look dead after a harsh summer or extended dry conditions.
You don't say where you live so I can't comment on durability. The plant is pretty tough though so it might survive it's recent treatment esp. since it sounds like it was dormant. I'm in southern NM and the plant greens up for a brief time in the summer and then again in the Fall or early winter. Usually in time to get hammered by a freeze and then it goes back to looking dead.
Not my favorite plant, they really get ripped apart by high winds in our area, they need severe pruning to look nice and they look dead too much of the year. I'd rather spend my water $$ on something else.
Keep in mind it's not a tree, just a giant shrub.

No problem, you just bareroot planted a dormant plant. FWIW, it's native and grows profusely in Southern California and can be a shrub or a tree. Theodore Payne Foundation, Rancho Santa Ana Botanic Garden, Las Pilitas Nursery websites can guide you to watering requirements to establish new plants and whether plants are deciduous, summer or winter dormant.