Having looked at this more carefully, my original answer stands:
As far as I can see, there is no “(conductor)” subkey in the image you posted and I would not expect one, as “conductor” has its own tag and is not one of the “performer:instrument” tags.
I thought I put the default of “tags to blank” as including “performer:orchestra, performer:choir, performer:choir vocals” with the ensemble_names source being used to replace these. This should do exactly what you want.
I appreciate that there are a lot of options, but I also provided a lot of defaults which can be used as a starting point. Take backups of picard.ini before saving new options, so that you can partially revert if necessary without having to revert to all the defaults.
Hope that helps.