Spring straps are God's gift to shore divers. Adding a set to your fins will be money well spent. They don and doff with ease.
Yes. And are indestructible, entanglement free, and won't detach themselves from the fins at the worst possible moment.
As your fins seat onto your booties they self adjust.
To some extent. A specific spring strap will fit a wide range of boot sizes, but if you're out of that range, they can't be adjusted. An ill fitting spring strap can be worse than even the worst rubber strap. Make sure to pick the right size!