Are v-brakes universal in size (kids vs adults)?
They are universal except for a very few models called mini V brakes, which use short pull brake levers as opposed to long pull. These stand out as having very short arms compared to most.
Shimano and Tektro make a lot of the good economical repair v-brakes. The model numbers change over time.
Reworking splayed out noodle cradles is a pretty common repair. It usually happens more from people getting frustrated and being rough with them than any kind of material weakness, so it's not likely to do the same thing again. I do it using either a slip joint plier or a Knipex plier-wrench. Of course I could imagine it being mangled enough that replacement is more prudent.