Lets back up.
I first tried APA 6th and inserted the citation in the footnote and edited the citation in the footnote to Author (Year) and it worked fine in Endnote X8 on a windows machine in Word 365. I see the APA 6th settings are “same as citation”.
I was also able to edit the short form to get that to show up (but the short form is only invoked when it is the second time cited in a footnote).
I stopped there, so I could get a more clear idea of what you are trying to achieve?
Exactly what do you want when in the footnote and you want the year to disambugate rather than the title? You want a fuller citation or full reference the first time? Is there also a bibliography? Are there Journal/publisher instructions that you can provide that explain these requirements?
Then can you put your current output styles in a zip and attach them? (I still don’t think this forum will allow .ens file attachments, but I haven’t tried again lately).