She's got a peach of a gun.
She can tailor tha ammot to the job or scenario. She can shoot either light ,medium, or high velocity ammo through it. Since the .22lrf or .38 Special are good beginner guns that's already been covered by her with the 686.
If she wants to shoot the .357 magnum rounds right off that's her choice,too.
Yes, it might be too much at the start and as McGunner has stated flinch is something that has to be considered. So going with the lowered power rounds would be good advice.
There are also those who are the exception to that. We are not there physically to know. Her call. It would be bad if flinch or other bad habits did enter in right away, but she's stated that is covered as well in getting instruction from someone else.
In a lot of cases husbands or boyfriends can be a bad choice to be the ones to do the instructing. A lot of reasons for that. Yes, nothing might happen.
But a lot of us have to look at things realistically,step back, and let others do the teaching. The male contingents can give support and sometimes training if needed.
Many savvy gun instructors recommend starting new shooters out on the .22lrf cartridge. There are many good reasons, many already stated in this thread, that it is a good starting point and go on from there.
The .38 Special is also a good choice with the right type of ammo for the introduction and then go on from there. No harm, no foul.
Yes, other calibers can be used for training and insruction. It has to be a common sense step by step process.