If ab initio is really everything it is supposed to be and she had at least a year online, she should have been fully capable of flying.
After a year, she should be up to speed. We'll have to see if she had that much experience
Even if she was weak, (assumedly because of inexperience not cognitive ability.) the only way to learn is to do.
Of course. I'd rather learn to land in challenging conditions as a FO with an experienced captain with me. When the flying is at the limits of the airplane's capabilities the captain needs to step in and get the job done. Save the instruction for a less challenging day.
There is a reason that the FARs allow a 121 captain to operate as an instructor. He/she is expected to teach when necessary. A capt. should always be prepared to take the airplane but there are not many instances in which he/she should as a rule not allow the fo to fly.
I think crosswinds in excess of 30kts is a good example
The only blanket exception I can think of is if the CA is new to the airplane or the operation and is not yet convinced of his/her own ability.
If the captain is comfortable letting the FO fly the plane when they are not comfortable doing it themself, there's a problem