Question about molting, someone please clarify.

Not all parrots molt in the same way, so it's tough to say exactly how long it may take for your new Quaker baby to grow new flight feathers. The widely varying answers you got actually are true-- a molt can last only a few weeks, or it may take several months. My QP Ralph has slow, gradual molts lasting up to 7 months. The Amazon parrot I had, George, molted twice a year, each molt lasting about six weeks. A friend has a Severe Macaw who molts gradually year-round. But your QP will grow new flight feathers, sooner or later.

I've noticed with my indoor birds that their molts tend to be more gradual.   Little bit here, little bit there, pretty much throughout the year, but more at some times than at others.  My chickens always molted all at once, one time a year, like most wild birds.  I think it is driven by the light cycle, so birds exposed to regular seasons are a little more predictable.

A bird that loses a feather outside of a normal molt will usually grow a new one right away.  A damaged or clipped feather, though, waits for the normal molt to replace it.  Not all feathers are always replaced every year, so I have to agree that there's just no sure answer for you.

I hope she was at least allowed to fledge properly before they gave her the poor clip.  That's a mean thing to do to a really young bird.