Yes, you are right, sorry, it is Alt-A.
Now: if you have an action like "Capitalize First Letter" and you want to assign a shortcut then rename it to
&Captitalize First Letter
and you can call it with the combination
As for the second thing: AFAIK there is currently no way to select individual fields of a file with the mouse. Or the keyboard. So in general, there is no way to select individual fields for copying.
Or is there?
The way I see it:
You select one file that has the master data. You copy the data.
Now you select the target files. And ... would have to have a dialogue which lets you select the fields that should get updated.
This is one concept I could think of.
The implemented concept however is a little different:
You select all the files, the source and the target file.
You then select in the tag panel the field where you want to update the data and select the data from the dropdown list.
Repeat this for all fields (this then is sort of the dialogue to select the fields).
Then press save.
This approach also has a solution for ambiguities if you have selected more than one file as source file. You can determine the best data for each field even though it may come from different sources.
Also, you do not have to disable the pasting, if more than one file had been selected during copy.
The effect is the same: you copy selected data from one file to many others.
Just another personal note: I think both concepts still have a little snag: they only work with fields that are already visible in the tag panel (or if you stick to the c&p solution from the files list) as a column.
It would be even better, if the dropdown-list mechanism would not only work in the tag panel but also in the Extended Tags dialogue. AFAIK you do not get any suggestions in the Extended Tags dialogue.